Pub Date : 2020-01-02DOI: 10.1080/08905436.2019.1710843
Mohd Hafez Mohd Isa, Nur Hashimah Shamsudin, N. Al-Shorgani, F. A. Alsharjabi, M. S. Kalil
ABSTRACT Biosurfactants or microbial surfactants are structurally diverse and contribute to reducing surface and interfacial tension. Apart from being isolated from municipal waste and oil contaminated soil, biosurfactant-producing Bacillus spp. can also be found in fermented foods. Bacillus subtilis produce surfactant, which exhibits antibacterial activity against various pathogenic bacteria. In this study, surfactant-producing Bacillus were isolated from traditional fermented food namely; budu (fish sauce), cincalok (fermented small shrimps), tempeh (fermented soybeans) and tapai ubi kayu (fermented cassava). Identification of surfactin-producing bacteria was conducted using 16S rRNA which indicated that surfactin-producing strains isolated from budu and tempeh are Bacillus subtilis while strains from cincalok and tapai ubi kayu are Bacillus amyloliquefaciens with a sequence similarity of 99%. Characterization of surfactin was carried out by High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LCMS). HLPC analyzes identified major peaks contributing to the presence of surfactin. LCMS analysis detected specific mass to charge ratio (m/z) which contributed to the presence of maximum thirteen surfactin isoforms. Surfactin produced by the isolated strains also exhibited antibacterial activity toward pathogenic bacteria, namely Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Streptococcus pneumoniae, Salmonella Typhimurium, Serratia marcescens and Klebsiella pneumoniae. All isolated strains from the Malaysian fermented food types investigated in this study were able to produce surfactin. In addition, antibacterial screening via agar well diffusion, measurements of MBC and MIC show surfactin produced by the isolated strains have antibacterial activities toward certain Gram-positive and Gram-negative bacteria tested in this study.
摘要生物表面活性剂或微生物表面活性剂结构多样，有助于降低表面和界面张力。除了从城市垃圾和石油污染的土壤中分离出来外，在发酵食品中也可以发现产生生物表面活性剂的芽孢杆菌。枯草芽孢杆菌产生表面活性剂，对各种致病菌具有抗菌活性。本研究从传统发酵食品中分离得到表面活性剂产生芽孢杆菌；budu（鱼露）、cincalok（发酵小虾）、tempeh（发酵大豆）和tapai ubi kayu（发酵木薯）。利用16S rRNA对产表面活性素的细菌进行了鉴定，结果表明，从budu和tempeh分离的产表面活性蛋白的菌株为枯草芽孢杆菌，而从cincalok和tapai ubi-kayu分离的菌株为解淀粉芽孢杆菌，序列相似性为99%。采用高效液相色谱法（HPLC）和液相色谱-质谱法（LCMS）对表面活性素进行了表征。HLPC分析鉴定的对表面活性素的存在有贡献的主峰。LCMS分析检测到比质荷比（m/z），这有助于存在最多13种表面活性素异构体。分离菌株产生的表面活性素对致病菌也表现出抗菌活性，即蜡样芽孢杆菌、单核细胞增多性李斯特菌、金黄色葡萄球菌、肺炎链球菌、鼠伤寒沙门氏菌、粘质沙雷氏菌和肺炎克雷伯菌。本研究中调查的所有来自马来西亚发酵食品类型的分离菌株都能产生表面活性素。此外，通过琼脂扩散进行抗菌筛选，MBC和MIC的测量表明，分离菌株产生的表面活性素对本研究中测试的某些革兰氏阳性菌和革兰氏阴性菌具有抗菌活性。
{"title":"Evaluation of antibacterial potential of biosurfactant produced by surfactin-producing Bacillus isolated from selected Malaysian fermented foods","authors":"Mohd Hafez Mohd Isa, Nur Hashimah Shamsudin, N. Al-Shorgani, F. A. Alsharjabi, M. S. Kalil","doi":"10.1080/08905436.2019.1710843","DOIUrl":"https://doi.org/10.1080/08905436.2019.1710843","url":null,"abstract":"ABSTRACT Biosurfactants or microbial surfactants are structurally diverse and contribute to reducing surface and interfacial tension. Apart from being isolated from municipal waste and oil contaminated soil, biosurfactant-producing Bacillus spp. can also be found in fermented foods. Bacillus subtilis produce surfactant, which exhibits antibacterial activity against various pathogenic bacteria. In this study, surfactant-producing Bacillus were isolated from traditional fermented food namely; budu (fish sauce), cincalok (fermented small shrimps), tempeh (fermented soybeans) and tapai ubi kayu (fermented cassava). Identification of surfactin-producing bacteria was conducted using 16S rRNA which indicated that surfactin-producing strains isolated from budu and tempeh are Bacillus subtilis while strains from cincalok and tapai ubi kayu are Bacillus amyloliquefaciens with a sequence similarity of 99%. Characterization of surfactin was carried out by High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LCMS). HLPC analyzes identified major peaks contributing to the presence of surfactin. LCMS analysis detected specific mass to charge ratio (m/z) which contributed to the presence of maximum thirteen surfactin isoforms. Surfactin produced by the isolated strains also exhibited antibacterial activity toward pathogenic bacteria, namely Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Streptococcus pneumoniae, Salmonella Typhimurium, Serratia marcescens and Klebsiella pneumoniae. All isolated strains from the Malaysian fermented food types investigated in this study were able to produce surfactin. In addition, antibacterial screening via agar well diffusion, measurements of MBC and MIC show surfactin produced by the isolated strains have antibacterial activities toward certain Gram-positive and Gram-negative bacteria tested in this study.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1710843","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46795111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/08905436.2019.1711112
Ting Xue, Xuehai Zheng, X. Su, Duo Chen, Kui Liu, Xue Yuan, Ronghua Lin, Luqiang Huang, Wenjin He, Jinmao Zhu, Youqiang Chen
ABSTRACT Transglutaminase-catalyzed reactions can be used widely to modify the functional properties of food proteins, biopharmaceuticals and in tissue engineering. Transglutaminase-producing organisms obtained from natural screening have a low ability to produce enzymes, and the obtained enzyme generally has low activity and poor substrate specificity, which limit its industrial applications. Of 100 isolates collected from five air-dried soil samples, 20 exhibited the typical growth characteristics of Actinomycetes. Of these 20 isolates, S-1and S-2 resulted in 0.47 and 0.30 U/mL transglutaminase production, respectively. Based on phenotypic and the 16S rRNA gene-sequence data, the isolate S-1 was confirmed as Streptomyces mobaraensis. We produced Transetta (DE3)/PET-32(a)-YC2 mutants in Escherichia coli exhibiting improved MTGase activity and production from the screened microbial transglutaminase-producing strain by directed evolution of the MTGase gene using epPCR combined with construction and overexpression of the PET-32(a)-YC2. The activity of Transetta (DE3)/pET-32a-YC2 TGase (3.03 U/mL) in E. coli growth supernatant was 1.5 and 1.8-fold above that of the control Transetta (DE3)/pET-32a-MTGase strain (2.02 U/mL) and Transetta (DE3)/pET-32a strain (1.68 U/mL), respectively. Under the optimized conditions, the content of target protein and MTGase activity by the MTGase gene expression in Transetta (DE3)/pET-32a-YC2 (26.2% and 4.99 U/mL) were 2.07 and 1.65-fold greater than control through optimization of different parameters. These results suggest that directed evolution of the MTGase gene from Streptomyces mobaraensis can effectively enhance the MTGase activity and protein expression in E. coli. This method of enhanced expression of active MTGase in E. coli may be valuable for food and other industrial applications. Graphical Abstract Numerous studies suggest that transglutaminase-catalyzed reactions can be used widely to modify the functional properties of food proteins, biopharmaceuticals and in tissue engineering. Transglutaminase-producing organisms obtained from natural screening have a low ability to ferment and produce enzymes, and the obtained enzyme generally has low activity and poor substrate specificity, which limit its industrial applications. In this work, we screened the isolate S-1 was Streptomyces mobaraensis from five air-dried soil samples according to the phenotypic and the 16S rRNA gene-sequencing. We produced Transetta (DE3)/PET-32(a)-YC2 mutants exhibiting improved MTGase activity and production from the screened microbial transglutaminase-producing strain by directed evolution of the MTGase gene using epPCR combined with construction and overexpression of the PET-32(a)-YC2. The activity of Transetta (DE3)/pET-32a-YC2 TGase (3.03 U/mL) was 1.5-fold above that of the control Transetta (DE3)/pET-32a-MTGase strain (2.02 U/mL). To further improve the yield of transglutaminase for the higher transglutaminase-producing stra
{"title":"Directed evolution of the transglutaminase from Streptomyces mobaraensis and its enhanced expression in Escherichia coli","authors":"Ting Xue, Xuehai Zheng, X. Su, Duo Chen, Kui Liu, Xue Yuan, Ronghua Lin, Luqiang Huang, Wenjin He, Jinmao Zhu, Youqiang Chen","doi":"10.1080/08905436.2019.1711112","DOIUrl":"https://doi.org/10.1080/08905436.2019.1711112","url":null,"abstract":"ABSTRACT Transglutaminase-catalyzed reactions can be used widely to modify the functional properties of food proteins, biopharmaceuticals and in tissue engineering. Transglutaminase-producing organisms obtained from natural screening have a low ability to produce enzymes, and the obtained enzyme generally has low activity and poor substrate specificity, which limit its industrial applications. Of 100 isolates collected from five air-dried soil samples, 20 exhibited the typical growth characteristics of Actinomycetes. Of these 20 isolates, S-1and S-2 resulted in 0.47 and 0.30 U/mL transglutaminase production, respectively. Based on phenotypic and the 16S rRNA gene-sequence data, the isolate S-1 was confirmed as Streptomyces mobaraensis. We produced Transetta (DE3)/PET-32(a)-YC2 mutants in Escherichia coli exhibiting improved MTGase activity and production from the screened microbial transglutaminase-producing strain by directed evolution of the MTGase gene using epPCR combined with construction and overexpression of the PET-32(a)-YC2. The activity of Transetta (DE3)/pET-32a-YC2 TGase (3.03 U/mL) in E. coli growth supernatant was 1.5 and 1.8-fold above that of the control Transetta (DE3)/pET-32a-MTGase strain (2.02 U/mL) and Transetta (DE3)/pET-32a strain (1.68 U/mL), respectively. Under the optimized conditions, the content of target protein and MTGase activity by the MTGase gene expression in Transetta (DE3)/pET-32a-YC2 (26.2% and 4.99 U/mL) were 2.07 and 1.65-fold greater than control through optimization of different parameters. These results suggest that directed evolution of the MTGase gene from Streptomyces mobaraensis can effectively enhance the MTGase activity and protein expression in E. coli. This method of enhanced expression of active MTGase in E. coli may be valuable for food and other industrial applications. Graphical Abstract Numerous studies suggest that transglutaminase-catalyzed reactions can be used widely to modify the functional properties of food proteins, biopharmaceuticals and in tissue engineering. Transglutaminase-producing organisms obtained from natural screening have a low ability to ferment and produce enzymes, and the obtained enzyme generally has low activity and poor substrate specificity, which limit its industrial applications. In this work, we screened the isolate S-1 was Streptomyces mobaraensis from five air-dried soil samples according to the phenotypic and the 16S rRNA gene-sequencing. We produced Transetta (DE3)/PET-32(a)-YC2 mutants exhibiting improved MTGase activity and production from the screened microbial transglutaminase-producing strain by directed evolution of the MTGase gene using epPCR combined with construction and overexpression of the PET-32(a)-YC2. The activity of Transetta (DE3)/pET-32a-YC2 TGase (3.03 U/mL) was 1.5-fold above that of the control Transetta (DE3)/pET-32a-MTGase strain (2.02 U/mL). To further improve the yield of transglutaminase for the higher transglutaminase-producing stra","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1711112","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44143458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-02DOI: 10.1080/08905436.2019.1673171
Rutairat Suttisuwan, S. Phunpruch, Tanatorn Saisavoey, Papassara Sangtanoo, N. Thongchul, A. Karnchanatat
ABSTRACT The Synechococcus sp. VDW peptides were prepared by trypsin digestion, which was then purified by ultrafiltration with molecular weight cut off membranes of 10, 5 and 3 kDa. Among the fractions, the MW <3 kDa fraction exhibited high levels of inhibitory activity toward the NO radical scavenging activities with IC50 values of 34.51 ± 9.8 μg/mL. The MW <3 kDa fraction was purified by reversed-phase HPLC to yield four fractions. The 30–40 min sub-fraction with maximum NO radical scavenging activity (77.50 ± 0.55%) was selected for further analysis by Q-TOF ESI mass spectrometry. Five isolated peptides with amino acid sequences of AILQSYSAGKTK; 1,265.69 Da, ALNKTHLIQTK; 1,265.74 Da, LLVHAPVK; 875.55 Da, IPDAHPVK; 875.48 Da, and VVVLRDGAVQQLGTPR; 1,706.97 Da were identified. The MW <3 kDa fraction showed no cytotoxicity toward RAW264.7 macrophage cells. Quantitative RT-PCR results showed that the MW <3 kDa fraction reduced gene expression of pro-inflammatory cytokines iNOS, TNF-α, COX-2, and IL-6. The peptides isolated from the MW <3 kDa fractions represent potential model peptides to develop natural anti-inflammation food-grade ingredients, drugs, and cosmetic products.
摘要:采用胰蛋白酶酶切法制备聚珠球菌VDW多肽，并采用分子量分别为10、5和3 kDa的超滤分离纯化。其中，MW <3 kDa部位对NO自由基的清除活性具有较高的抑制作用，IC50值为34.51±9.8 μg/mL。用反相高效液相色谱法纯化分子量<3 kDa的部分，得到4个部分。选取清除NO自由基活性最高(77.50±0.55%)的30-40 min亚段，采用Q-TOF ESI质谱法进行进一步分析。AILQSYSAGKTK氨基酸序列的5个分离肽段;1,265.69 Da, ALNKTHLIQTK;1,265.74 Da, LLVHAPVK;875.55 Da, IPDAHPVK;875.48 Da，和VVVLRDGAVQQLGTPR;鉴定出1,706.97个Da。MW <3 kDa部分对RAW264.7巨噬细胞无细胞毒性。定量RT-PCR结果显示，MW < 3kda组分降低了促炎细胞因子iNOS、TNF-α、COX-2和IL-6的基因表达。从分子量<3 kDa组分中分离的肽代表了开发天然抗炎症食品级成分、药物和化妆品的潜在模型肽。
{"title":"Isolation and characterization of anti-inflammatory peptides derived from trypsin hydrolysis of microalgae protein (Synechococcus sp. VDW)","authors":"Rutairat Suttisuwan, S. Phunpruch, Tanatorn Saisavoey, Papassara Sangtanoo, N. Thongchul, A. Karnchanatat","doi":"10.1080/08905436.2019.1673171","DOIUrl":"https://doi.org/10.1080/08905436.2019.1673171","url":null,"abstract":"ABSTRACT The Synechococcus sp. VDW peptides were prepared by trypsin digestion, which was then purified by ultrafiltration with molecular weight cut off membranes of 10, 5 and 3 kDa. Among the fractions, the MW <3 kDa fraction exhibited high levels of inhibitory activity toward the NO radical scavenging activities with IC50 values of 34.51 ± 9.8 μg/mL. The MW <3 kDa fraction was purified by reversed-phase HPLC to yield four fractions. The 30–40 min sub-fraction with maximum NO radical scavenging activity (77.50 ± 0.55%) was selected for further analysis by Q-TOF ESI mass spectrometry. Five isolated peptides with amino acid sequences of AILQSYSAGKTK; 1,265.69 Da, ALNKTHLIQTK; 1,265.74 Da, LLVHAPVK; 875.55 Da, IPDAHPVK; 875.48 Da, and VVVLRDGAVQQLGTPR; 1,706.97 Da were identified. The MW <3 kDa fraction showed no cytotoxicity toward RAW264.7 macrophage cells. Quantitative RT-PCR results showed that the MW <3 kDa fraction reduced gene expression of pro-inflammatory cytokines iNOS, TNF-α, COX-2, and IL-6. The peptides isolated from the MW <3 kDa fractions represent potential model peptides to develop natural anti-inflammation food-grade ingredients, drugs, and cosmetic products.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1673171","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47339532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-02DOI: 10.1080/08905436.2019.1673173
R. Bailone, L. D. Aguiar, R. Roça, R. Borra, Tatiana Corrêa, H. Janke, H. Fukushima
ABSTRACT Toxicity studies in mammals continue to be the most appropriate model for predicting risk in humans, but they tend to be expensive and time-consuming. In the aftermath of the genetic sequencing of zebrafish (Danio rerio), this species is highly genetically homologous to humans. The use of the zebrafish model to assess food toxicity is already a reality as it is capable of biological processes difficult to reproduce in vitro. Studies of complex mechanisms of absorption, distribution, metabolism, and excretion as well as cellular and tissue interactions are of great information value resulting in time, space and cost savings, when compared to studies with rodents. This review addresses the relevance of zebrafish model in food safety research, both in the use of ingredients and approved and generally recognized as safe food additives as well as for establishing levels of safe food contaminant residues present in the environment. Toxicological screening using the zebrafish model integrate the evaluation of teratogenicity, cardiotoxicity, hepatotoxicity, genotoxicity, neurotoxicity, endocrine toxicity, reproductive and behavioral aspects. These are important endpoints for food safety assessment, which take substantially less time than in mammalian tests. Furthermore, it serves well as a screening test follow-up for validating favorable results in murine models, hence accelerating the risk assessment process of products submitted for approval and registration, prioritizing safe compounds and reducing unnecessary costs in subsequent mammalian studies. In conclusion, the zebrafish model can be a useful tool for food safety tests; however, additional studies are needed to further validate this model for registration of new food ingredients and additives.
{"title":"“Zebrafish as an animal model for food safety research: trends in the animal research”","authors":"R. Bailone, L. D. Aguiar, R. Roça, R. Borra, Tatiana Corrêa, H. Janke, H. Fukushima","doi":"10.1080/08905436.2019.1673173","DOIUrl":"https://doi.org/10.1080/08905436.2019.1673173","url":null,"abstract":"ABSTRACT Toxicity studies in mammals continue to be the most appropriate model for predicting risk in humans, but they tend to be expensive and time-consuming. In the aftermath of the genetic sequencing of zebrafish (Danio rerio), this species is highly genetically homologous to humans. The use of the zebrafish model to assess food toxicity is already a reality as it is capable of biological processes difficult to reproduce in vitro. Studies of complex mechanisms of absorption, distribution, metabolism, and excretion as well as cellular and tissue interactions are of great information value resulting in time, space and cost savings, when compared to studies with rodents. This review addresses the relevance of zebrafish model in food safety research, both in the use of ingredients and approved and generally recognized as safe food additives as well as for establishing levels of safe food contaminant residues present in the environment. Toxicological screening using the zebrafish model integrate the evaluation of teratogenicity, cardiotoxicity, hepatotoxicity, genotoxicity, neurotoxicity, endocrine toxicity, reproductive and behavioral aspects. These are important endpoints for food safety assessment, which take substantially less time than in mammalian tests. Furthermore, it serves well as a screening test follow-up for validating favorable results in murine models, hence accelerating the risk assessment process of products submitted for approval and registration, prioritizing safe compounds and reducing unnecessary costs in subsequent mammalian studies. In conclusion, the zebrafish model can be a useful tool for food safety tests; however, additional studies are needed to further validate this model for registration of new food ingredients and additives.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1673173","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41827359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-02DOI: 10.1080/08905436.2019.1673770
Li Wang, Yanfeng Liu, Fan Yang, Jianghua Li, Biduan Chen, G. Du
ABSTRACT Diacetyl imparts a characteristic buttery aroma to foods and beverages. However, when present at high levels in Maotai-flavor liquor, it generates an undesirable buttery off-odor. The aim of this study was to identify the diacetyl-producing microorganisms in Maotai-flavor liquor with an ultimate aim to develop methods that could reduce diacetyl production. To explore the microbial origin of diacetyl in Maotai-flavor liquor, the off-odor intensity and diacetyl content of stacking fermented grains, which are used in the production of Maotai-flavor liquor, were evaluated. Then, 16S rRNA V3-V4 high-throughput sequencing and the random forest algorithm were combined to analyze the potential diacetyl producers. The featured selection results indicated that Lactobacillus was the major diacetyl contributor in the fermented grains, followed by Staphylococcus, Weissella, Pediococcus, and Klebsiella. To verify this, 123 lactic acid bacteria (LAB) isolates were selected from the high diacetyl off-odor group samples, and the genus Lactobacillus accounted for more than 90% of the identified isolates. The results of our study showed that L. plantarum, L. pentosus, and L. fermentum were the major diacetyl-producing microorganisms (>90 mg/L). Moreover, the fermentation characteristics of the high-yield strain, L. plantarum MTL-09, showed that temperature and pH had strong effects on diacetyl production, which may offer a strategy for inhibiting the off-odor by controlling the pH or temperature during fermentation. The methods may also be useful for identification of key microorganisms for fermented foods and alcoholic beverages.
{"title":"Microbiome analysis and random forest algorithm-aided identification of the diacetyl-producing microorganisms in the stacking fermentation stage of Maotai-flavor liquor production","authors":"Li Wang, Yanfeng Liu, Fan Yang, Jianghua Li, Biduan Chen, G. Du","doi":"10.1080/08905436.2019.1673770","DOIUrl":"https://doi.org/10.1080/08905436.2019.1673770","url":null,"abstract":"ABSTRACT Diacetyl imparts a characteristic buttery aroma to foods and beverages. However, when present at high levels in Maotai-flavor liquor, it generates an undesirable buttery off-odor. The aim of this study was to identify the diacetyl-producing microorganisms in Maotai-flavor liquor with an ultimate aim to develop methods that could reduce diacetyl production. To explore the microbial origin of diacetyl in Maotai-flavor liquor, the off-odor intensity and diacetyl content of stacking fermented grains, which are used in the production of Maotai-flavor liquor, were evaluated. Then, 16S rRNA V3-V4 high-throughput sequencing and the random forest algorithm were combined to analyze the potential diacetyl producers. The featured selection results indicated that Lactobacillus was the major diacetyl contributor in the fermented grains, followed by Staphylococcus, Weissella, Pediococcus, and Klebsiella. To verify this, 123 lactic acid bacteria (LAB) isolates were selected from the high diacetyl off-odor group samples, and the genus Lactobacillus accounted for more than 90% of the identified isolates. The results of our study showed that L. plantarum, L. pentosus, and L. fermentum were the major diacetyl-producing microorganisms (>90 mg/L). Moreover, the fermentation characteristics of the high-yield strain, L. plantarum MTL-09, showed that temperature and pH had strong effects on diacetyl production, which may offer a strategy for inhibiting the off-odor by controlling the pH or temperature during fermentation. The methods may also be useful for identification of key microorganisms for fermented foods and alcoholic beverages.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1673770","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46095576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-02DOI: 10.1080/08905436.2019.1674157
Saif Ullah, M. Irfan, W. Sajjad, Qurrat ul ain Rana, F. Hasan, Samiullah Khan, M. Badshah, Aamer Ali Shah
ABSTRACT A xylanase-producing bacterium Bacillus pumilus K22 was isolated from hot spring located in Manghopir area, Karachi, Pakistan. The enzyme was purified to homogeneity by acetone precipitation and size exclusion chromatography. The molecular weight was determined to be approximately 24 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The purified xylanase retained its activity at wide range of temperature (20-70°C) and pH (5.0–10.0) with maximum stability at 50°C and pH 8.0. Xylanase activity was inhibited by Zn2+, Cu2+, and Hg2+ metal ions while it remained stable in the presence of Mn2+, Ca2+ and Mg2+. The activity was also inhibited by chemical reagents such as EDTA, PMSF, and β-mercaptoethanol. The enzyme was stable in the presence of all organic solvents (20%) except formaldehyde and glycerol, which inhibited its activity. Treatment of tomato pulp with purified xylanase-increased juice yield (30%), clarity (9%), and reducing sugars (69%), indicating an improvement in physico-chemical characteristics of the tomato pulp.
{"title":"Production of an alkali-stable xylanase from Bacillus pumilus K22 and its application in tomato juice clarification","authors":"Saif Ullah, M. Irfan, W. Sajjad, Qurrat ul ain Rana, F. Hasan, Samiullah Khan, M. Badshah, Aamer Ali Shah","doi":"10.1080/08905436.2019.1674157","DOIUrl":"https://doi.org/10.1080/08905436.2019.1674157","url":null,"abstract":"ABSTRACT A xylanase-producing bacterium Bacillus pumilus K22 was isolated from hot spring located in Manghopir area, Karachi, Pakistan. The enzyme was purified to homogeneity by acetone precipitation and size exclusion chromatography. The molecular weight was determined to be approximately 24 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The purified xylanase retained its activity at wide range of temperature (20-70°C) and pH (5.0–10.0) with maximum stability at 50°C and pH 8.0. Xylanase activity was inhibited by Zn2+, Cu2+, and Hg2+ metal ions while it remained stable in the presence of Mn2+, Ca2+ and Mg2+. The activity was also inhibited by chemical reagents such as EDTA, PMSF, and β-mercaptoethanol. The enzyme was stable in the presence of all organic solvents (20%) except formaldehyde and glycerol, which inhibited its activity. Treatment of tomato pulp with purified xylanase-increased juice yield (30%), clarity (9%), and reducing sugars (69%), indicating an improvement in physico-chemical characteristics of the tomato pulp.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1674157","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48484518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-02DOI: 10.1080/08905436.2019.1673172
M. Öztürk, Cansu Önal, Ndeye Mareme Ba
ABSTRACT Bile salt hydrolase (BSH) is a gut-bacterial enzyme that influences human health by altering the host fat digestion and cellular energy generation. BSH is essential for deconjugation of the glycine or taurine-conjugated bile salts in the small intestine of humans. Therefore, BSH may be a key microbiome target for the designing of new measures to control some diseases in humans. BSHs, a member of the N-terminal nucleophile (Ntn) hydrolase superfamily, exhibit higher variation in substrate specificity. The phenylalanine-129 (F129) and leucine-138 (L138) in loop III of BSH, thought to be responsible for substrate specificity, are partially conserved in this superfamily. In this study, the aromatic-hydrophobic F129 and aliphatic-hydrophobic L138 of C-terminally His-tagged BSH from Lactobacillus plantarum B14 (LbBSH) was substituted for aliphatic-hydrophobic isoleucine (I) and negatively charged polar glutamate (E) amino acid, respectively, by site-directed mutagenesis and characterized using an Escherichia coli BLR(DE3) expression system. Although both mutations resulted in an assembled and stable recombinant BSHs (rBSHs), they altered the catalytic activity and substrate specificity of rBSH. This is the first experimental finding which confirmed that F129 and L138 were critical amino acids for the catalytic activity and substrate specificity turnover of BSH.
{"title":"Critical F129 and L138 in loop III of bile salt hydrolase (BSH) in Lactobacillus plantarum B14 are essential for the catalytic activity and substrate specificity","authors":"M. Öztürk, Cansu Önal, Ndeye Mareme Ba","doi":"10.1080/08905436.2019.1673172","DOIUrl":"https://doi.org/10.1080/08905436.2019.1673172","url":null,"abstract":"ABSTRACT Bile salt hydrolase (BSH) is a gut-bacterial enzyme that influences human health by altering the host fat digestion and cellular energy generation. BSH is essential for deconjugation of the glycine or taurine-conjugated bile salts in the small intestine of humans. Therefore, BSH may be a key microbiome target for the designing of new measures to control some diseases in humans. BSHs, a member of the N-terminal nucleophile (Ntn) hydrolase superfamily, exhibit higher variation in substrate specificity. The phenylalanine-129 (F129) and leucine-138 (L138) in loop III of BSH, thought to be responsible for substrate specificity, are partially conserved in this superfamily. In this study, the aromatic-hydrophobic F129 and aliphatic-hydrophobic L138 of C-terminally His-tagged BSH from Lactobacillus plantarum B14 (LbBSH) was substituted for aliphatic-hydrophobic isoleucine (I) and negatively charged polar glutamate (E) amino acid, respectively, by site-directed mutagenesis and characterized using an Escherichia coli BLR(DE3) expression system. Although both mutations resulted in an assembled and stable recombinant BSHs (rBSHs), they altered the catalytic activity and substrate specificity of rBSH. This is the first experimental finding which confirmed that F129 and L138 were critical amino acids for the catalytic activity and substrate specificity turnover of BSH.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1673172","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42304250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-03DOI: 10.1080/08905436.2019.1616299
J. D. Leal-Gutiérrez, R. Mateescu
ABSTRACT Beef palatability is a complex concept and could be described through an array of features such as tenderness, juiciness and flavor traits. Improving the eating experience when consuming beef and the ability to accurately inform the consumers of the expected eating quality when the product is purchased are critical challenges. In this review, we discuss the current knowledge of quantitative and molecular genetic aspects of palatability and discuss implications of genetic manipulation for the cattle industry.
{"title":"Genetic basis of improving the palatability of beef cattle: current insights","authors":"J. D. Leal-Gutiérrez, R. Mateescu","doi":"10.1080/08905436.2019.1616299","DOIUrl":"https://doi.org/10.1080/08905436.2019.1616299","url":null,"abstract":"ABSTRACT Beef palatability is a complex concept and could be described through an array of features such as tenderness, juiciness and flavor traits. Improving the eating experience when consuming beef and the ability to accurately inform the consumers of the expected eating quality when the product is purchased are critical challenges. In this review, we discuss the current knowledge of quantitative and molecular genetic aspects of palatability and discuss implications of genetic manipulation for the cattle industry.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1616299","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45882272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-03DOI: 10.1080/08905436.2019.1618713
Felipe Jadán Piedra
ABSTRACT Selective determination of lactic acid in dry-fermented sausages is an indicator of quality and its presence prevents the growth of pathogenic bacteria. The analysis of lactic acid represents a high cost for the relevant food industries. The use of an enzymatic sensor would allow to reduce the time and cost of this analysis. An enzymatic sensor employing lactate oxidase (LacOx) with the immobilized enzyme system in combination with an oxygen electrode was optimized to determine the lactic acid content in dry-fermented sausages. In this study using LacOx from Pediococcus sp., a voltage of −600 mV, low volumes of reaction and the amperometric signal obtained due to the oxygen depletion (consumed oxygen) during the lactic acid oxidation was recorded at 15 s in the immobilized enzyme sensor so that the reaction rates (slope) were related to the lactic acid content. A positive linear relationship between the consumed oxygen as a function of time (mg O2/L*s−1) and the lactic acid concentration in the range of 250–600 μM, with a coefficient ofR2 = 0.9936 for the immobilized enzyme system, was determined. The immobilized enzyme sensor showed a high specificity KM = 0.865 and sensitivity of 0.25 mM and was stable enough to allow the reutilization of the membranes up to 20 times without loss of activity, where 90% of its initial activity remained after 45 days. The analysis of lactic acid with the immobilized enzyme system in dry-fermented sausages revealed very good agreement with the determination performed through standard HPLC methodology using the same linear range in both methods, which validated the use of this sensor as an alternative technique to evaluate cured meat quality.
{"title":"Selective determination of lactic acid in dry-fermented sausages using a sensor based on immobilized lactate oxidase","authors":"Felipe Jadán Piedra","doi":"10.1080/08905436.2019.1618713","DOIUrl":"https://doi.org/10.1080/08905436.2019.1618713","url":null,"abstract":"ABSTRACT Selective determination of lactic acid in dry-fermented sausages is an indicator of quality and its presence prevents the growth of pathogenic bacteria. The analysis of lactic acid represents a high cost for the relevant food industries. The use of an enzymatic sensor would allow to reduce the time and cost of this analysis. An enzymatic sensor employing lactate oxidase (LacOx) with the immobilized enzyme system in combination with an oxygen electrode was optimized to determine the lactic acid content in dry-fermented sausages. In this study using LacOx from Pediococcus sp., a voltage of −600 mV, low volumes of reaction and the amperometric signal obtained due to the oxygen depletion (consumed oxygen) during the lactic acid oxidation was recorded at 15 s in the immobilized enzyme sensor so that the reaction rates (slope) were related to the lactic acid content. A positive linear relationship between the consumed oxygen as a function of time (mg O2/L*s−1) and the lactic acid concentration in the range of 250–600 μM, with a coefficient ofR2 = 0.9936 for the immobilized enzyme system, was determined. The immobilized enzyme sensor showed a high specificity KM = 0.865 and sensitivity of 0.25 mM and was stable enough to allow the reutilization of the membranes up to 20 times without loss of activity, where 90% of its initial activity remained after 45 days. The analysis of lactic acid with the immobilized enzyme system in dry-fermented sausages revealed very good agreement with the determination performed through standard HPLC methodology using the same linear range in both methods, which validated the use of this sensor as an alternative technique to evaluate cured meat quality.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1618713","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46590982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-03DOI: 10.1080/08905436.2019.1618323
C. Hung, L. Cheng, C. Yeh
ABSTRACT Brazzein is an attractive sweetener candidate because of its sugar-like taste, high sweetness, and good stability at high temperature and wide pH range. This study was aimed to express and purify bioactive recombinant brazzein (rBrazzein). The rBrazzein gene was synthesized according to the preferred codons of Bacillus subtilis and successfully expressed in Escherichia coli and Bacillus licheniformis. In E. coli host, lower induction temperature of 30°C increased soluble rBrazzein (Ebrazzein) at high level. In B. licheniformis host, two signal peptides (Sec type and Tat type) were evaluated for the expression of rBarzzein in B. subtilis and B. licheniformis. However, only the Sec-type signal peptide guided the secretion expression of rBrazzein in B. licheniformis. The rBrazzein was expressed steadily and the highest yield reached about 57 mg/L at 36 h by small-scale fermentation. The purification procedure of rBrazzein by B. licheniformis (Bbrazzein) was thus established. Approximately 5 mg/L purified rBrazzein was obtained and the purity was 85%. The conformational state of rBrazzeins was confirmed by circular dichroism. The bioactivities of rBrazzeins were evaluated by sweet taste testing. The Bbrazzein and Ebrazzein were 266 times and 400 times sweeter than sucrose on a weight basis, respectively. The formation of disulfide bonds were both confirmed by LC/MS/MS and MALDI-TOF. The CD analysis indicated that Ebrazzein has a similar secondary structure with natural brazzein, which explained why Ebrazzein had a higher intensity of sweetness. This study demonstrated that B. licheniformis system is useful to produce active recombinant brazzein, and has potential food industry applications.
{"title":"Functional expression of recombinant sweet-tasting protein brazzein by Escherichia coli and Bacillus licheniformis","authors":"C. Hung, L. Cheng, C. Yeh","doi":"10.1080/08905436.2019.1618323","DOIUrl":"https://doi.org/10.1080/08905436.2019.1618323","url":null,"abstract":"ABSTRACT Brazzein is an attractive sweetener candidate because of its sugar-like taste, high sweetness, and good stability at high temperature and wide pH range. This study was aimed to express and purify bioactive recombinant brazzein (rBrazzein). The rBrazzein gene was synthesized according to the preferred codons of Bacillus subtilis and successfully expressed in Escherichia coli and Bacillus licheniformis. In E. coli host, lower induction temperature of 30°C increased soluble rBrazzein (Ebrazzein) at high level. In B. licheniformis host, two signal peptides (Sec type and Tat type) were evaluated for the expression of rBarzzein in B. subtilis and B. licheniformis. However, only the Sec-type signal peptide guided the secretion expression of rBrazzein in B. licheniformis. The rBrazzein was expressed steadily and the highest yield reached about 57 mg/L at 36 h by small-scale fermentation. The purification procedure of rBrazzein by B. licheniformis (Bbrazzein) was thus established. Approximately 5 mg/L purified rBrazzein was obtained and the purity was 85%. The conformational state of rBrazzeins was confirmed by circular dichroism. The bioactivities of rBrazzeins were evaluated by sweet taste testing. The Bbrazzein and Ebrazzein were 266 times and 400 times sweeter than sucrose on a weight basis, respectively. The formation of disulfide bonds were both confirmed by LC/MS/MS and MALDI-TOF. The CD analysis indicated that Ebrazzein has a similar secondary structure with natural brazzein, which explained why Ebrazzein had a higher intensity of sweetness. This study demonstrated that B. licheniformis system is useful to produce active recombinant brazzein, and has potential food industry applications.","PeriodicalId":12347,"journal":{"name":"Food Biotechnology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/08905436.2019.1618323","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45107814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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