Pub Date : 2023-08-24DOI: 10.3390/fermentation9090784
V. Ahuja, A. Arora, Shikhabaghel Chauhan, S. Thakur, C. Jeyaseelan, D. Paul
The European Union has recommended that about 10–50% of the global energy requirement should be supplemented by waste biomass resources by 2050 in order to achieve the objective of having net-zero-emission economies. This has led to intensive research being conducted on developing appropriate biofuel production technologies using advanced or integrated systems to tackle local, national, and global energy challenges using waste feedstock. Researchers have realized the potential of microbes (e.g., yeast strains) for bioenergy production. For this paper, both non-oleaginous and oleaginous yeasts were reviewed, with a specific focus being placed on their diversity in metabolism and tolerance to the various challenges that arise from the use of waste feedstock and influence bioprocessing. Gathering in-depth knowledge and information on yeast metabolism has paved the way for newer and better technologies to employ them for consolidated biorefineries to not only produce biofuels but also to cut down process expenses and decrease the risks of net carbon emissions. The rationale for using yeast strains improved by metabolic engineering and genetic manipulation that can substantially meet the challenges of alternate fuel resources is also described in this paper. This literature review presents the advantages and disadvantages of yeast-based biofuel production and highlights the advancements in technologies and how they contrast to conventional methods. Over the last decade, scientific publications have endorsed the idea of biorefineries for environmentally friendly, cost-effective, and sustainable biofuel production.
{"title":"Yeast-Mediated Biomass Valorization for Biofuel Production: A Literature Review","authors":"V. Ahuja, A. Arora, Shikhabaghel Chauhan, S. Thakur, C. Jeyaseelan, D. Paul","doi":"10.3390/fermentation9090784","DOIUrl":"https://doi.org/10.3390/fermentation9090784","url":null,"abstract":"The European Union has recommended that about 10–50% of the global energy requirement should be supplemented by waste biomass resources by 2050 in order to achieve the objective of having net-zero-emission economies. This has led to intensive research being conducted on developing appropriate biofuel production technologies using advanced or integrated systems to tackle local, national, and global energy challenges using waste feedstock. Researchers have realized the potential of microbes (e.g., yeast strains) for bioenergy production. For this paper, both non-oleaginous and oleaginous yeasts were reviewed, with a specific focus being placed on their diversity in metabolism and tolerance to the various challenges that arise from the use of waste feedstock and influence bioprocessing. Gathering in-depth knowledge and information on yeast metabolism has paved the way for newer and better technologies to employ them for consolidated biorefineries to not only produce biofuels but also to cut down process expenses and decrease the risks of net carbon emissions. The rationale for using yeast strains improved by metabolic engineering and genetic manipulation that can substantially meet the challenges of alternate fuel resources is also described in this paper. This literature review presents the advantages and disadvantages of yeast-based biofuel production and highlights the advancements in technologies and how they contrast to conventional methods. Over the last decade, scientific publications have endorsed the idea of biorefineries for environmentally friendly, cost-effective, and sustainable biofuel production.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41577285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-24DOI: 10.3390/fermentation9090782
Sirine Saadaoui, B. Erable, L. Etchevery, A. Cherif, H. Chouchane
Bioelectrochemical systems (BESs), rather than physicochemical processes, are used for wastewater remediation, electricity production, and zero carbon dioxide emission. Textile effluents contain organic and inorganic compounds that can fuel BESs. The main goal of this study was to understand the interplay between the anode material, its surface area, the potential applied to the working electrode (WE), and the concentration of the co-substrate, and how these factors lead to the formation of highly efficient thermohalophilic bioanodes (THB) retrieved from Chott El Djerid (SCD) hypersaline sediment for the treatment of synthetic textile wastewater. To this end, twenty-seven bioanode formation experiments were designed using a Box-Behnken matrix and response surface methodology to understand concomitant interactions. All experiments were conducted in electrochemical reactors of final volume 750 mL inoculated with 80% of enrichment medium containing three azo dyes at a concentration of 300 ppm and 20% of biocatalyst microbial SCD source, at 45 °C. The optimal levels were predicted using NemrodW software as carbon felt (CF) anode material, 6 cm2 anode surface, 7 g/L glucose concentration, and −0.1 V applied potential. These theoretical results were experimentally validated, using maximum current output of 5.23 ± 0.30 A/m2, decolorization rate of 100%, and a chemical oxygen demand (COD) removal rate of 96 ± 1%. Illumina Miseq results revealed that bacterial community harbored the bioanode was dominated at phylum level by Firmicutes (67.1%). At the species level, the biofilm was mainly colonized by Orenia metallireducens species (59.5%). Obtained findings show a promising application of THB in the degradation of recalcitrant molecules as well as for the energy recovery.
生物电化学系统（BES），而不是物理化学过程，用于废水修复、电力生产和零二氧化碳排放。纺织废水含有可为BES提供燃料的有机和无机化合物。本研究的主要目标是了解阳极材料、其表面积、施加到工作电极（WE）的电势和共基质的浓度之间的相互作用，以及这些因素如何导致从Chott El Djerid（SCD）高盐沉积物中回收的高效热卤性生物节点（THB）的形成，用于处理合成纺织废水。为此，使用Box-Behnken矩阵和响应面方法设计了27个生物节点形成实验，以了解伴随的相互作用。所有实验均在最终体积为750mL的电化学反应器中进行，在45°C下接种80%的含有浓度为300ppm的三种偶氮染料和20%的生物催化剂微生物SCD源的富集介质。使用NemrodW软件预测最佳水平，即碳毡（CF）阳极材料、6 cm2阳极表面、7 g/L葡萄糖浓度和−0.1 V外加电位。实验验证了这些理论结果，最大电流输出为5.23±0.30A/m2，脱色率为100%，化学需氧量（COD）去除率为96±1%。Illumina Miseq结果显示，在门水平上，厚壁菌门（67.1%）占生物节点所在的细菌群落的主导地位。在物种水平上，生物膜主要由Orenia metallireducens物种定植（59.5%）。研究结果表明，THB在降解难降解分子和能量回收方面具有很好的应用前景。
{"title":"Joint Multi-Optimization of an Extremophilic Microbial Bioanode for Mitigation of Mixed Hazardous Azo Dyes in Textile Synthetic Wastewater","authors":"Sirine Saadaoui, B. Erable, L. Etchevery, A. Cherif, H. Chouchane","doi":"10.3390/fermentation9090782","DOIUrl":"https://doi.org/10.3390/fermentation9090782","url":null,"abstract":"Bioelectrochemical systems (BESs), rather than physicochemical processes, are used for wastewater remediation, electricity production, and zero carbon dioxide emission. Textile effluents contain organic and inorganic compounds that can fuel BESs. The main goal of this study was to understand the interplay between the anode material, its surface area, the potential applied to the working electrode (WE), and the concentration of the co-substrate, and how these factors lead to the formation of highly efficient thermohalophilic bioanodes (THB) retrieved from Chott El Djerid (SCD) hypersaline sediment for the treatment of synthetic textile wastewater. To this end, twenty-seven bioanode formation experiments were designed using a Box-Behnken matrix and response surface methodology to understand concomitant interactions. All experiments were conducted in electrochemical reactors of final volume 750 mL inoculated with 80% of enrichment medium containing three azo dyes at a concentration of 300 ppm and 20% of biocatalyst microbial SCD source, at 45 °C. The optimal levels were predicted using NemrodW software as carbon felt (CF) anode material, 6 cm2 anode surface, 7 g/L glucose concentration, and −0.1 V applied potential. These theoretical results were experimentally validated, using maximum current output of 5.23 ± 0.30 A/m2, decolorization rate of 100%, and a chemical oxygen demand (COD) removal rate of 96 ± 1%. Illumina Miseq results revealed that bacterial community harbored the bioanode was dominated at phylum level by Firmicutes (67.1%). At the species level, the biofilm was mainly colonized by Orenia metallireducens species (59.5%). Obtained findings show a promising application of THB in the degradation of recalcitrant molecules as well as for the energy recovery.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48268243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-23DOI: 10.3390/fermentation9090780
B. Dowd, M. Tuohy
Fungi are increasingly recognised as being able to inhabit extreme environments. The deep sea is considered an extreme environment because of its low temperatures, high hydrostatic and lithostatic pressures, 3.5% salinity, and low oxygen, nutrient and light availability. Fungi inhabiting the deep sea may have evolved to produce proteins that allow them to survive these conditions. Investigation and characterisation of fungal lignocellulolytic enzymes from extreme environments like the deep sea is needed, as they may have unusual adaptations that would be useful in industry. This work, therefore, aimed to profile in detail the lignocellulolytic capabilities of fungi isolated from deep-sea sediments in the Atlantic Ocean, and a comparative lignocellulolytic terrestrial isolate. The isolates were strains of Emericellopsis maritima, Penicillium chrysogenum, P. antarcticum and Talaromyces stollii. Lignocellulolytic enzyme induction was achieved using liquid-state fermentation (LSF) with wheat bran as the main carbon source, while enzyme characteristics were evaluated using biochemical assays and gel-based proteomics. This study revealed that the isolates were halotolerant, produced xylanase over wide pH and temperature ranges, and produced a variety of glycoside hydrolase and feruloyl esterase activities. The T. stollii secretome demonstrated remarkable levels of exo-glycoside hydrolase activity, with xylanase activity optimum between pH 1.5–6.0 and temperatures between 1–60 °C, making this isolate an ideal candidate for biotechnological applications. This study is the first to quantitatively characterise xylanase activities and exo-glycoside hydrolase activities secreted by E. maritima, P. antarcticum and a marine T. stollii strain. This study is also the first to quantitatively characterise xylanase activities by a marine strain of P. chrysogenum during LSF.
{"title":"Induction and Characterisation of Lignocellulolytic Activities from Novel Deep-Sea Fungal Secretomes","authors":"B. Dowd, M. Tuohy","doi":"10.3390/fermentation9090780","DOIUrl":"https://doi.org/10.3390/fermentation9090780","url":null,"abstract":"Fungi are increasingly recognised as being able to inhabit extreme environments. The deep sea is considered an extreme environment because of its low temperatures, high hydrostatic and lithostatic pressures, 3.5% salinity, and low oxygen, nutrient and light availability. Fungi inhabiting the deep sea may have evolved to produce proteins that allow them to survive these conditions. Investigation and characterisation of fungal lignocellulolytic enzymes from extreme environments like the deep sea is needed, as they may have unusual adaptations that would be useful in industry. This work, therefore, aimed to profile in detail the lignocellulolytic capabilities of fungi isolated from deep-sea sediments in the Atlantic Ocean, and a comparative lignocellulolytic terrestrial isolate. The isolates were strains of Emericellopsis maritima, Penicillium chrysogenum, P. antarcticum and Talaromyces stollii. Lignocellulolytic enzyme induction was achieved using liquid-state fermentation (LSF) with wheat bran as the main carbon source, while enzyme characteristics were evaluated using biochemical assays and gel-based proteomics. This study revealed that the isolates were halotolerant, produced xylanase over wide pH and temperature ranges, and produced a variety of glycoside hydrolase and feruloyl esterase activities. The T. stollii secretome demonstrated remarkable levels of exo-glycoside hydrolase activity, with xylanase activity optimum between pH 1.5–6.0 and temperatures between 1–60 °C, making this isolate an ideal candidate for biotechnological applications. This study is the first to quantitatively characterise xylanase activities and exo-glycoside hydrolase activities secreted by E. maritima, P. antarcticum and a marine T. stollii strain. This study is also the first to quantitatively characterise xylanase activities by a marine strain of P. chrysogenum during LSF.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42577038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-23DOI: 10.3390/fermentation9090781
Erick M. Peña-Lucio, M. Chávez-González, L. Londoño-Hernandez, Héctor A. Ruiz, J. Martínez-Hernández, M. Govea-Salas, Pradeep Nediyaparambil Sukumaran, Sabu Abdulhameed, Cristóbal N. Aguilar
Tea (Camellia sinensis) is an evergreen shrub that is recognized worldwide for its functional properties. The current global production of green tea is approximately 5.3 million tons per year. Green tea processing has severely affected the generation of agro-industrial waste. One strategy for reducing waste accumulation is the revalorization of agro-industrial wastes via solid-state fermentation (SSF). The aim of this study was to valorize green tea processing residues to produce tannase under SSF using an endemic strain from Western Ghats, Aspergillus niger TBG 28A. SSF was performed in Erlenmeyer flasks with spent green tea leaves inoculated with spores of A. niger TBG 28A. Bioprocess optimization was carried out by employing the Box–Benkhen experimental design, achieving a high enzymatic yield of 246.82 (U/g). The present study shows the complexity of the degradation of tannins and the different patterns of expression of fungal tannase obtained from A. niger TBG 28 A. The enzyme was further purified to obtain a fold purification of 16.35% and a molecular mass of 150 kDa. Producing tannase with a novel strain of A. niger TBG 28A is an interesting strategy to revalorize green tea waste.
{"title":"Solid-State Fermentation of Green Tea Residues as Substrates for Tannase Production by Aspergillus niger TBG 28A: Optimization of the Culture Conditions","authors":"Erick M. Peña-Lucio, M. Chávez-González, L. Londoño-Hernandez, Héctor A. Ruiz, J. Martínez-Hernández, M. Govea-Salas, Pradeep Nediyaparambil Sukumaran, Sabu Abdulhameed, Cristóbal N. Aguilar","doi":"10.3390/fermentation9090781","DOIUrl":"https://doi.org/10.3390/fermentation9090781","url":null,"abstract":"Tea (Camellia sinensis) is an evergreen shrub that is recognized worldwide for its functional properties. The current global production of green tea is approximately 5.3 million tons per year. Green tea processing has severely affected the generation of agro-industrial waste. One strategy for reducing waste accumulation is the revalorization of agro-industrial wastes via solid-state fermentation (SSF). The aim of this study was to valorize green tea processing residues to produce tannase under SSF using an endemic strain from Western Ghats, Aspergillus niger TBG 28A. SSF was performed in Erlenmeyer flasks with spent green tea leaves inoculated with spores of A. niger TBG 28A. Bioprocess optimization was carried out by employing the Box–Benkhen experimental design, achieving a high enzymatic yield of 246.82 (U/g). The present study shows the complexity of the degradation of tannins and the different patterns of expression of fungal tannase obtained from A. niger TBG 28 A. The enzyme was further purified to obtain a fold purification of 16.35% and a molecular mass of 150 kDa. Producing tannase with a novel strain of A. niger TBG 28A is an interesting strategy to revalorize green tea waste.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41329107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-22DOI: 10.3390/fermentation9090779
Jiajia Liu, G. Yao, Xiukun Wan, Fuli Wang, Penggang Han, Shaoheng Bao, Kang Wang, Tianyu Song, Hui Jiang
γ-bisabolene is a monocyclic sesquiterpene with various biological activities; it has also been approved as a food additive. Additionally, the hydrogenated form of bisabolene is considered as a potential alternative to D2 diesel. Saccharomyces cerevisiae has the ability to produce a large amount of acetyl-CoA in both cytosol and peroxisomes, which serves as a precursor in terpene biosynthesis. In this study, AcTPS5 was identified as a new γ-bisabolene synthase. By expressing AcTPS5 and the mevalonate pathway in peroxisomes, γ-bisabolene titer was achieved at 125.0 mg/L. Deleting the peroxisome autophagy gene atg36 further improved γ-bisabolene production to 216.9 mg/L. The implementation of dual cytoplasmic–peroxisomal engineering further boosted γ-bisabolene production to 296.4 mg/L. Finally, through increasing the acetyl-CoA supply and down-regulating the expression of ERG9, γ-bisabolene production was achieved at 584.14 mg/L in shake-flask fermentation and 2.69 g/L in fed-batch fermentation, which is the highest reported production of γ-bisabolene to date. The strategy presented in this study provides an efficient approach for terpene production in S. cerevisiae.
{"title":"Highly Efficient Biosynthesis of γ-Bisabolene with a New Sesquiterpene Synthase AcTPS5 by Dual Cytoplasmic-Peroxisomal Engineering in Saccharomyces cerevisiae","authors":"Jiajia Liu, G. Yao, Xiukun Wan, Fuli Wang, Penggang Han, Shaoheng Bao, Kang Wang, Tianyu Song, Hui Jiang","doi":"10.3390/fermentation9090779","DOIUrl":"https://doi.org/10.3390/fermentation9090779","url":null,"abstract":"γ-bisabolene is a monocyclic sesquiterpene with various biological activities; it has also been approved as a food additive. Additionally, the hydrogenated form of bisabolene is considered as a potential alternative to D2 diesel. Saccharomyces cerevisiae has the ability to produce a large amount of acetyl-CoA in both cytosol and peroxisomes, which serves as a precursor in terpene biosynthesis. In this study, AcTPS5 was identified as a new γ-bisabolene synthase. By expressing AcTPS5 and the mevalonate pathway in peroxisomes, γ-bisabolene titer was achieved at 125.0 mg/L. Deleting the peroxisome autophagy gene atg36 further improved γ-bisabolene production to 216.9 mg/L. The implementation of dual cytoplasmic–peroxisomal engineering further boosted γ-bisabolene production to 296.4 mg/L. Finally, through increasing the acetyl-CoA supply and down-regulating the expression of ERG9, γ-bisabolene production was achieved at 584.14 mg/L in shake-flask fermentation and 2.69 g/L in fed-batch fermentation, which is the highest reported production of γ-bisabolene to date. The strategy presented in this study provides an efficient approach for terpene production in S. cerevisiae.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48261815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-21DOI: 10.3390/fermentation9080778
Sultan Shaikh, Naim Rashid, Gordon McKay, H. Mackey
This review paper provides an overview of various types of photobioreactors (PBRs) that could be used for the production of polyhydroxyalkanoates (PHAs) using anoxygenic photoheterotrophs, with a focus on the design and operation of these systems. The paper highlights the potential of different PBRs based on reactor geometry and growth mode, and also examines the advantages and disadvantages of each PBR type and summarizes their suitability for PNSB-PHA production. The optimization of reactor design and operation is crucial for maximizing PNSB growth and PHA productivity. The self-immobilization of bacteria in granular sludge is a promising technology for wastewater treatment and the production of PHAs, while grooved-surface PBRs and porous-substrate PBRs have limitations due to difficult biomass harvesting in the former and the presence of aerobic conditions incongruent with PNSB culturing in the latter. Limitations exist with all solutions for maximizing rapid growth and maintaining high biomass concentrations due to the requirements of phototrophic growth.
{"title":"Photobioreactor Design for Polyhydroxyalkanoate Production Using Anoxygenic Photoheterotrophs: A Review","authors":"Sultan Shaikh, Naim Rashid, Gordon McKay, H. Mackey","doi":"10.3390/fermentation9080778","DOIUrl":"https://doi.org/10.3390/fermentation9080778","url":null,"abstract":"This review paper provides an overview of various types of photobioreactors (PBRs) that could be used for the production of polyhydroxyalkanoates (PHAs) using anoxygenic photoheterotrophs, with a focus on the design and operation of these systems. The paper highlights the potential of different PBRs based on reactor geometry and growth mode, and also examines the advantages and disadvantages of each PBR type and summarizes their suitability for PNSB-PHA production. The optimization of reactor design and operation is crucial for maximizing PNSB growth and PHA productivity. The self-immobilization of bacteria in granular sludge is a promising technology for wastewater treatment and the production of PHAs, while grooved-surface PBRs and porous-substrate PBRs have limitations due to difficult biomass harvesting in the former and the presence of aerobic conditions incongruent with PNSB culturing in the latter. Limitations exist with all solutions for maximizing rapid growth and maintaining high biomass concentrations due to the requirements of phototrophic growth.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46297284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-21DOI: 10.3390/fermentation9080776
Pu-yi Zhu, Yilin Wang, Hui Bai, Jing Feng, Rui Zhang, Duo Bu, Zeng Dan, Wei Li, Xuebin Lu
Polyaluminum chloride (PAC) is used widely and increasingly in wastewater treatment plants, resulting in its inevitably high production in sludge. Previous studies have indicated that the production of short-chain fatty acids (SCFAs) is inhibited by the existence of PAC in sludge anaerobic fermentation, so it is necessary to study how to promote sludge anaerobic fermentation under low concentrations of PAC. In this study, sodium citrate (SC) was first used to improve the efficiency of anaerobic fermentation under low concentrations of PAC. The results showed that the production of SCFAs increased with SC, especially when the ratio of PAC to SC was 1:2, and the maximum production of SCFAs reached 2890 mg/L, which is 2.5 times more than when PAC only exists. The mechanism studies showed that SC could remove the Al3+ in the sludge floc, which led to deflocculation of the sludge floc, accelerated the destruction of extracellular polymers (EPS), and released soluble substances in the sludge. At the same time, the key enzymes that were bound and hidden originally in the sludge were also released, which promoted the further degradation of organic matter and shortened the anaerobic fermentation period. However, the higher concentration of SC was not conducive to sludge dehydration. Therefore, the optimal distribution ratio of PAC to SC should be 1:1. This study provides a new idea for the research and practical application of sludge anaerobic fermentation.
{"title":"Research on the Promotion of Sludge Anaerobic Fermentation with Sodium Citrate under Low Concentrations of Polyaluminum Chloride","authors":"Pu-yi Zhu, Yilin Wang, Hui Bai, Jing Feng, Rui Zhang, Duo Bu, Zeng Dan, Wei Li, Xuebin Lu","doi":"10.3390/fermentation9080776","DOIUrl":"https://doi.org/10.3390/fermentation9080776","url":null,"abstract":"Polyaluminum chloride (PAC) is used widely and increasingly in wastewater treatment plants, resulting in its inevitably high production in sludge. Previous studies have indicated that the production of short-chain fatty acids (SCFAs) is inhibited by the existence of PAC in sludge anaerobic fermentation, so it is necessary to study how to promote sludge anaerobic fermentation under low concentrations of PAC. In this study, sodium citrate (SC) was first used to improve the efficiency of anaerobic fermentation under low concentrations of PAC. The results showed that the production of SCFAs increased with SC, especially when the ratio of PAC to SC was 1:2, and the maximum production of SCFAs reached 2890 mg/L, which is 2.5 times more than when PAC only exists. The mechanism studies showed that SC could remove the Al3+ in the sludge floc, which led to deflocculation of the sludge floc, accelerated the destruction of extracellular polymers (EPS), and released soluble substances in the sludge. At the same time, the key enzymes that were bound and hidden originally in the sludge were also released, which promoted the further degradation of organic matter and shortened the anaerobic fermentation period. However, the higher concentration of SC was not conducive to sludge dehydration. Therefore, the optimal distribution ratio of PAC to SC should be 1:1. This study provides a new idea for the research and practical application of sludge anaerobic fermentation.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46493664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
(1) Background: Previous studies have indicated that ferulic acid esterase (FAE), cellulase and xylanase have synergistic effects in lignocellulose degradation, and the cutting stage has a major impact on silages. Whether these additives affect the silages at different cutting stages is unclear. (2) Methods: Sudangrass height at the tested cutting stages was 1.8 m (S1) and 2.0 m (S2). The silage from the two cutting stages was treated with FAE-producing Lactobacillus plantarum (LP), cellulase and xylanase (CX) and a combination of LP and CX (LP+CX) for 30 and 60 days. (3) Results: Compared with CK, adding LP+CX significantly decreased the pH and the content of neutral detergent fiber (NDF) and acidic detergent fiber (ADF) (p < 0.05) and increased the lactic acid (LA) concentration (p < 0.05), dry matter (DM) content and crude protein content. Adding LP+CX effectively degraded lignocellulose in sudangrass, and the NDF and ADF degradation rates at the two stages were all more than 30%. In comparison, cutting at the S2 stage led to a lower pH and higher LA and DM contents (p < 0.05). Additives and the cutting stage exerted a strong effect on the silage microbial community, and Firmicutes and Lactiplantibacillus became the most dominant bacterial phyla and genera, especially at the S2 stage. (4) Conclusions: The results suggest that FAE-producing L. plantarum, cellulase and xylanase had synergistic effects on sudangrass silages, especially at the S2 stage, and their use can thus serve as an efficient method for ensiling.
{"title":"Effects of Different Cutting Stages and Additives on the Fermentation Quality and Microbial Community of Sudangrass (Sorghum sudanense Stapf.) Silages","authors":"Qiang Yu, Mengxin Li, Yu Zhang, Jinyi Xu, Ping Li, Hong Sun, Yixiao Xie, Rui Dong, Yulong Zheng, Chao Chen","doi":"10.3390/fermentation9080777","DOIUrl":"https://doi.org/10.3390/fermentation9080777","url":null,"abstract":"(1) Background: Previous studies have indicated that ferulic acid esterase (FAE), cellulase and xylanase have synergistic effects in lignocellulose degradation, and the cutting stage has a major impact on silages. Whether these additives affect the silages at different cutting stages is unclear. (2) Methods: Sudangrass height at the tested cutting stages was 1.8 m (S1) and 2.0 m (S2). The silage from the two cutting stages was treated with FAE-producing Lactobacillus plantarum (LP), cellulase and xylanase (CX) and a combination of LP and CX (LP+CX) for 30 and 60 days. (3) Results: Compared with CK, adding LP+CX significantly decreased the pH and the content of neutral detergent fiber (NDF) and acidic detergent fiber (ADF) (p < 0.05) and increased the lactic acid (LA) concentration (p < 0.05), dry matter (DM) content and crude protein content. Adding LP+CX effectively degraded lignocellulose in sudangrass, and the NDF and ADF degradation rates at the two stages were all more than 30%. In comparison, cutting at the S2 stage led to a lower pH and higher LA and DM contents (p < 0.05). Additives and the cutting stage exerted a strong effect on the silage microbial community, and Firmicutes and Lactiplantibacillus became the most dominant bacterial phyla and genera, especially at the S2 stage. (4) Conclusions: The results suggest that FAE-producing L. plantarum, cellulase and xylanase had synergistic effects on sudangrass silages, especially at the S2 stage, and their use can thus serve as an efficient method for ensiling.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43803362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-19DOI: 10.3390/fermentation9080773
E. Bouloumpasi, A. Skendi, Evangelos H. Soufleros
Yeast assimilable nitrogen (YAN), besides the oenological parameters (sugar content, titratable acidity, and pH) in grape musts of sixteen native and international varieties of Vitis vinifera cultivated in six regions of Northern Greece, was assessed in the frame of the present study. Low levels of YAN are frequently thought to be the cause of problematic fermentations and originate significant changes in the organoleptic aspects of the finished product. The objective of this multi-variety study was to assess factors affecting the YAN amount and composition in technologically mature grapes and, therefore, to evaluate the necessity of YAN supplementation with ammonium salts in musts across different native and international grape varieties. Free amino nitrogen was measured colorimetrically, ammoniacal nitrogen was measured enzymatically, and their values for each must sample were summed to obtain the total amount of YAN. Statistical analysis was carried out including principal component analysis (PCA) to discover relationships among must samples and the parameters studied. PCA analysis classified samples depending on grape varieties and region of origin, bringing knowledge about native and international cultivars of great commercial interest. Moreover, these findings could help to understand how commercial varieties can behave in different climates in the climate change context.
{"title":"Survey on Yeast Assimilable Nitrogen Status of Musts from Native and International Grape Varieties: Effect of Variety and Climate","authors":"E. Bouloumpasi, A. Skendi, Evangelos H. Soufleros","doi":"10.3390/fermentation9080773","DOIUrl":"https://doi.org/10.3390/fermentation9080773","url":null,"abstract":"Yeast assimilable nitrogen (YAN), besides the oenological parameters (sugar content, titratable acidity, and pH) in grape musts of sixteen native and international varieties of Vitis vinifera cultivated in six regions of Northern Greece, was assessed in the frame of the present study. Low levels of YAN are frequently thought to be the cause of problematic fermentations and originate significant changes in the organoleptic aspects of the finished product. The objective of this multi-variety study was to assess factors affecting the YAN amount and composition in technologically mature grapes and, therefore, to evaluate the necessity of YAN supplementation with ammonium salts in musts across different native and international grape varieties. Free amino nitrogen was measured colorimetrically, ammoniacal nitrogen was measured enzymatically, and their values for each must sample were summed to obtain the total amount of YAN. Statistical analysis was carried out including principal component analysis (PCA) to discover relationships among must samples and the parameters studied. PCA analysis classified samples depending on grape varieties and region of origin, bringing knowledge about native and international cultivars of great commercial interest. Moreover, these findings could help to understand how commercial varieties can behave in different climates in the climate change context.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46143384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-08-19DOI: 10.3390/fermentation9080774
K. Hoffstadt, D. Cheenakula, M. Nikolausz, S. Krafft, H. Harms, I. Kuperjans
The increasing share of renewable electricity in the grid drives the need for sufficient storage capacity. Especially for seasonal storage, power-to-gas can be a promising approach. Biologically produced methane from hydrogen produced from surplus electricity can be used to substitute natural gas in the existing infrastructure. Current reactor types are not or are poorly optimized for flexible methanation. Therefore, this work proposes a new reactor type with a plug flow reactor (PFR) design. Simulations in COMSOL Multiphysics ® showed promising properties for operation in laminar flow. An experiment was conducted to support the simulation results and to determine the gas fraction of the novel reactor, which was measured to be 29%. Based on these simulations and experimental results, the reactor was constructed as a 14 m long, 50 mm diameter tube with a meandering orientation. Data processing was established, and a step experiment was performed. In addition, a kLa of 1 h−1 was determined. The results revealed that the experimental outcomes of the type of flow and gas fractions are in line with the theoretical simulation. The new design shows promising properties for flexible methanation and will be tested.
{"title":"Design and Construction of a New Reactor for Flexible Biomethanation of Hydrogen","authors":"K. Hoffstadt, D. Cheenakula, M. Nikolausz, S. Krafft, H. Harms, I. Kuperjans","doi":"10.3390/fermentation9080774","DOIUrl":"https://doi.org/10.3390/fermentation9080774","url":null,"abstract":"The increasing share of renewable electricity in the grid drives the need for sufficient storage capacity. Especially for seasonal storage, power-to-gas can be a promising approach. Biologically produced methane from hydrogen produced from surplus electricity can be used to substitute natural gas in the existing infrastructure. Current reactor types are not or are poorly optimized for flexible methanation. Therefore, this work proposes a new reactor type with a plug flow reactor (PFR) design. Simulations in COMSOL Multiphysics ® showed promising properties for operation in laminar flow. An experiment was conducted to support the simulation results and to determine the gas fraction of the novel reactor, which was measured to be 29%. Based on these simulations and experimental results, the reactor was constructed as a 14 m long, 50 mm diameter tube with a meandering orientation. Data processing was established, and a step experiment was performed. In addition, a kLa of 1 h−1 was determined. The results revealed that the experimental outcomes of the type of flow and gas fractions are in line with the theoretical simulation. The new design shows promising properties for flexible methanation and will be tested.","PeriodicalId":48535,"journal":{"name":"Fermentation-Basel","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47110142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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