Biocatalysis and agricultural biotechnology最新文献

Vachellia gummifera is a nitrogen-fixing shrub endemic to Morocco, and represents a suitable candidate for reforestation programs in dry areas. In this study, we identified seven root microsymbionts of V. gummifera, and determined their phenotypic characteristics, Plant Growth-Promoting (PGP) activities and their symbiotic efficiency. The bacteria were isolated from root nodules of the plant grown in Moroccan forest soils located in arid and semi-arid regions. The 16S rRNA gene sequences analysis of seven isolates showed similarity values ranging from 99.85% to 99.92% with Sinorhizobium fredii USDA205^T. The phenotypic analyses displayed that the strains use different carbohydrates, mainly mono and di-saccharides, as a sole carbon source, and 13 out of 15 amino acids tested as the sole nitrogen source. The strains have variable tolerance to heavy metals, but are sensitive to salinity and high temperature, as no one grew in the presence of 2% NaCl (w/v) or at 40 °C, respectively. On the other hand, the strains grew in a very high osmotic stress environment induced by PEG 6000 (20% w/v), and they all grow in a pH range between 6.5 and 9. The strains possess PGP activities, such as phosphate solubilization, siderophore, and indole acetic acid production. Inoculation under axenic conditions showed that the strains increased the aerial biomass of inoculated plants up to 217%, whereas the relative symbiotic efficiency percentages (74.87–140,3%) showed that most strains are very efficient. From all these results we concluded that our strains may be proposed as inoculum for large-scale applications, such as reforestation programs.

The rhizosphere is one of the most dynamic sites in plants, where continuous interaction is going on between the complex microbial community and the plant cell. These microorganisms impart different effects on plants, depending on the type of microorganism and the surrounding environment. Such interactions basically depend on the composition of root exudates secreted by the plant, and these interactions have either beneficial or deleterious effects on the plant. The beneficial microbes play a very diverse role in the growth and survival of the plant in different environmental states. With an increase in food demand for the growing population on limited crop land, there is a requirement for the tool to have the potential to enhance crop productivity in an eco-friendly manner. So, rhizospheric engineering is the preferred tool for enhanced crop productivity, where different microbes with different potentials need to be identified for sustainable crop productivity. In the rhizosphere, a microbial consortium has been generated, with the group of microorganisms having the ability to overcome the effects of stress factors on the survival of the associated plant. Such microbial consortiums identified against different environmental stresses are allowed to remain associated with the plant root in different stress conditions for sustainable crop productivity.

Contemporary agricultural practices extensively depend on synthetic fertilizers to boost crop productivity by providing essential nutrients. While effective in the short term, their prolonged use can negatively affect soil fertility and disrupt the nutrient balance of the rhizospheric microbiome. As an innovative and environmentally sustainable alternative, nanotechnology introduces nanofertilizers that offer targeted delivery and efficient nutrient utilization. Nanoparticles (NPs) have demonstrated versatility in plant research, functioning as growth regulators, antimicrobial agents, biosensors, fertilizers, and pesticides. Additionally, plants play a significant role in the advancement of nanotechnology through their ability to synthesize NPs and inspire plant-based nanobionics. Despite their potential, the complex interactions between NPs and plants, especially in the context of heavy metal (HM) stress, remain insufficiently explored. This selective review focuses on the role of the plant microbiome in alleviating HM stress and how NPs can be utilized in phytoremediation strategies. We examine the dual mechanisms of direct heavy metal absorption by plants and the modulation of the plant microbiome, highlighting how NPs can influence both plant health and microbial diversity under HM stress. By investigating these interconnected aspects, this review aims to provide insights into nutrient management and environmental remediation, promoting a more comprehensive understanding of the synergistic effects between NPs, plants, and their associated microbiomes.

The effect of natural or controlled solid-state fermentation using single or mixed probiotic strains on the nutritional, bioactive and phytochemical constituents, and antioxidant activities of tamarind seeds was evaluated. Tamarind seeds were subjected to either controlled solid-state fermentation (37 °C, 72 h) using either Bacillus subtilis only or Bacillus subtilis co-cultured with probiotics Lactobacillus spp. (Lactobacillus fermentum, Lactobacillus rhamnosus GG, Lactobacillus brevis, and Lactobacillus delbrueckii) or natural fermentation while unfermented tamarind seeds served as control. The changes in the nutritional composition, peptide content, antioxidative properties (Ferric reducing antioxidant power (FRAP) and DPPH radical scavenging activities) and total viable count of probiotics in fermented tamarind seed were evaluated using standard methods. The peptide content, crude protein, fat, and fibre (100.19 mg/g, 51.35, 9.50 and 5.10%), and FRAP and DPPH (0.55 and 21.60%) in unfermented tamarind seed were significantly (p < 0.05) lower than fermented tamarind seed (271.00–308 mg/g, 12, 62.84–64.02, 12.21–13.11 and 6.01–6.90, and 1.42–2.92 and 26.66–35.70%, respectively), after 72 h of fermentation. The total viable count in the tamarind seed fermented with Bacillus subtilis only was 1.2 × 10⁹ CFU/g while that co-cultured with probiotics ranged from 6 × 10⁸ to 9.9 × 10⁸ CFU/g after 72 h of fermentation. This study showed that a controlled solid-state fermentation using probiotics Lactobacillus co-cultured with Bacillus subtilis can significantly increase the peptide contents, and enhance the nutritional and antioxidant activities of tamarind seed while producing a condiment with significant probiotic potential.

Utilization of industrial side streams as nutrient source for cellular agriculture is a promising option to improve the sustainability of the production processes. The aim of the study was to evaluate usability of two liquid food industry side streams, potato cell fluid and acid whey, as nutrient source for production of food ingredients with plant cell cultures (arctic bramble (Rubus arcticus L.) and tobacco BY-2 (Nicotiana tabacum L.)) and filamentous fungi (Paecilomyces variotii, Rhizopus oligosporus and Trichoderma reesei). The side streams were found to contain various sugars and other potential nutrients suitable for the studied organisms. The side streams were used as a sole nutrient source (fungi) or as a replacement of selected nutrients in the growth media (fungi and plant cells) in flask scale cultivations. Acid whey was successfully used as a growth medium for filamentous fungi, but it inhibited plant cell growth presumably due to high organic acid content (14 g/l). Potato side stream was found suitable as a fungal and plant cell growth media supplement, and it was used together with glucose for filamentous fungi, or as a partial replacer of macronutrients for plant cells, in bioreactor cultivations yielding high fungal (up to 36 g/l dry weight) and good plant cell (9.5 g/l dry weight) biomass production. Analyses of the produced biomasses revealed good nutritional value in terms of amino acid (17–27 % of dry matter) and dietary fiber (23–30 % of dry matter) contents, giving good premises for utilization in human nutrition.

Hyperpigmentation often arises from an imbalance in melanogenesis, primarily due to the overexpression of tyrosinase (TYR). While the inhibition of TYR presents a common approach to skin whitening, it can lead to undesirable side effects. Thus, there is growing interest in safe and natural alternatives for TYR inhibition. Bioactive compounds and peptides sourced from split gill mushrooms hold promise in this regard. This study aims to optimize the conditions for papain-mediated hydrolysis of split gill mushroom protein to inhibit TYR activity, utilizing response surface methodology (RSM) and central composite design (CCD). Optimal conditions were determined at a temperature of 46.70 °C, a hydrolysis time of 217.09 min, and an enzyme-to-substrate ratio (E/S) of 1.1%. Under these conditions, the resulting hydrolysates exhibited significant TYR inhibition, with an IC₅₀ value of 117.86 μg/mL and a degree of hydrolysis (DH) of 87.97%. Further purification via ultrafiltration and RP-HPLC yielded a peptide, Tyr-Ala-Ser-Ile-Leu-Leu (YASILL or YL-6), identified through LC-Q-TOF-MS/MS, which competitively inhibited TYR. YL-6 demonstrated an IC₅₀ value of 3.97 mM for mono-phenolase activity and 6.75 mM for di-phenolase activity. Molecular docking analysis revealed hydrogen bonds and hydrophobic interactions between TYR and YL-6. Treatment of B16F10 cells with YL-6 across concentrations ranging from 10-3000 μM showed no cytotoxic effects.The inhibition of melanin synthesis was investigated via qRT-PCR along with Western blot in MITF, TYR, TRP-1, and TRP-2. The results obtained in this research may prove significant in guiding the development of commercially viable cosmetic products to whiten the skin.

The increasing demand for renewable energy sources has prompted a search for innovative and efficient approaches for biogas production. This study investigates the potential of achieving sustainable biogas production through a synergistic combination of biological pre-treatment and co-digestion of rice straw (RS) and sewage sludge (SS). The goal is to enhance the overall methane yield, mitigate substrate limitations, and optimize the biogas production process. In this study, rice straw and sewage sludge were anaerobically co-digested in ratios of 100:0, 70:30, 50:50, 30:70, and 30:70. It was observed that the co-digestion ratio of 70:30 is optimal to achieve maximum methane yield of 0.3 L CH₄/(g VS added). Biological pre-treatment with five different organisms Sphingobium sp., Paenibacillus sp., Microbacterium sp., Pseudomonas sp., and Stenotrophomonas sp. was also examined for RS and co-digested with SS at the optimized ratio to improve the degradability of RS. This pre-treatment strategy is anticipated to enhance the accessibility of microorganisms to substrates and accelerate the rates of hydrolysis. The biological pre-treatment resulted in a 20–23% improvement in methane yield compared to untreated substrates. Metagenomic studies revealed the dominance of Bacteroidetes, Firmicutes, and Proteobacteria, which are capable of utilizing lignocellulosic biomass and ultimately converting it to methane. The acetoclastic methanogensis is the major methane generating pathway which is supported by the complete dominance of genus Methanosaeta.

Melanin, a macromolecule derived from the oxidative polymerization of phenolic compounds, possesses notable bioactive attributes and serves as a crucial biological safeguard against deleterious environmental factors. Melanin originates in Streptomyces and is known for its antioxidative properties. This study aimed to characterize and evaluate the antioxidant activity of melanin obtained from Streptomyces lasalocidi NTB 42. Based on 16 S rRNA identification, strain NTB 42 was identified as Streptomyces lasalocidi NTB 42 (OR710932). During melanin biosynthesis, S. lasalocidi NTB 42 had the highest tyrosinase activity on day 5 and the highest L-3,4-dihydroxyphenylalanine concentration on day 6. Melanin NTB 42 exhibited polymorphic and irregular morphology. Melanin NTB 42 characteristics were analyzed using the A₆₅₀/A₅₀₀ ratio, UV–visible spectroscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography, dispersive X-ray spectroscopy, and thermal degradation products based on pyrolysis-gas chromatography-mass spectrometry were identified as eumelanin. The scavenging ability of NTB 42 melanin, as determined by the half maximal inhibitory concentration (IC₅₀), was 70.60 ± 0.40 μg/mL for 2,2-diphenyl-1-picrylhydrazyl and 176.76 ± 0.93 μg/mL for 2,2′-azino-bis(3-ethylbenzothiazolin-6-acid sulfonate radicals. The Fe-reducing power and total antioxidant capacity values were 114.05 ± 0.41 mg AAE/g melanin and 145.10 ± 0.56 mg AAE/g melanin, respectively. This study is the first attempt to characterize the antioxidant properties of eumelanin from S. lasalocidi NTB 42. The antioxidant ability of eumelanin NTB 42 against various free radicals shows promise for further development as an antioxidant.

This research was conducted to examine the effects of nano chitosan particles on seed germination and seedling growth of guar (Cyamopsis tetragonoloba L.) under osmotic stress conditions. This experiment was conducted in a factorial layout based on a completely randomized design with two factors and four replications. The experimental factors included: osmotic stress at five levels (0, −3, −6, −9 and −12 bar) and seed priming with nano chitosan particles at five concentrations (0, 50, 100, 200, and 300 ppm). The evaluated parameters in this study were alometric traits and enzymatic activities including proline, catalase, ascorbate peroxidase, superoxide dismutase, and total soluble sugar, as well as the content of chlorophyll a, b, and carotenoids. The results indicated the significant effect of most of the studied quantitative and qualitative traits. The highest values of seedling, plumule and radicle length (48.20, 17.79 and 30.15 mm, respectively), and the fresh weight of seedlings and plumule (0.9743 and 0.9192 g, respectively) were observed at a concentration of 200 ppm of chitosan nanoparticles. The highest amount of all studied parameters observed under non-stress conditions (control), and the lowest values of them obtained in −12 bar of osmotic stress. Furthermore, by increasing of osmotic stress levels, germination percentage and rate and seed vigor showed a decreasing trend about 56, 83 and 95% compared to the control. Besed on the interaction effects, the maximum values of seedling and plumule length were achieved with the application of 200 ppm chitosan nanoparticles in combination with no osmotic stress. Under non-osmotic conditions, concentrations of 300, 100, and 200 ppm chitosan led to the highest values of germination percentage and rate and seed vigor, respectively. Additionally, the highest percentage of normal seedlings (94%) and the lowest percentage of abnormal seedlings (zero) were obtained under the application of 200 ppm of nano chitosan and no osmotic stress. In relation to qualitative traits, the lowest values of soluble sugar and proline were obtained at the osmotic level of −12 bar. Moreover, the application of 200 ppm of nano chitosan and −6 bar of osmotic stress resulted in the highest levels of catalase, superoxide dismutase, ascorbate peroxidase, chlorophyll a, b, and carotenoids. As a whole, the results of the study demonstrated that seed priming with chitosan nanoparticles can reduce the negative effects of drought stress on guar seedlings. In addition, application of 200 ppm of this substance was the most suitable treatments that improve most quantitative and qualitative indices of guar. Keywords: Enzymatic activity, Nano particles, Priming, Seed structure.

Turmeric, scientifically known as Curcuma longa, is a herbaceous plant characterized by its rhizomatous nature with remarkable chemical composition and biologically active compounds. Lactic acid bacteria (LAB) have been observed to break down complex polyphenols into simpler, more bioactive compounds through fermentation. The success of the fermentation process relies on various factors to achieve the desired end product. This study's main goal was to assess the feasibility of using turmeric as a fermentable substrate for LAB, with the intention of creating a non-dairy fermented beverage. The investigation delved into the impact of several fermentation parameters, namely Fermentation Temperature, pH (Lemon juice concentration), Inoculum concentration, and Substrate concentration (Turmeric concentration), on the phytochemical and antioxidant properties of the lactic acid-fermented turmeric beverage (FTB). Statistical analysis revealed that a quadratic polynomial model could effectively illustrate how these fermentation parameters influenced the beverage's phytochemical and antioxidant qualities. Visualization through response surface plots revealed that these independent variables significantly influenced the beverage's total phenolic content, total flavonoid content, and antioxidant properties. Optimal fermentation conditions were identified to yield the highest levels of phenolic, flavonoid, and antioxidant content. These conditions included a Fermentation Temperature of 37.45 °C, a pH of 5.62, an Inoculum concentration of 5.12%v/v, and a Substrate (turmeric) concentration of 2.28%w/v. Under these precise conditions, experimental results closely aligned with predicted values for total phenolic content (57.46mg/100 ml), total flavonoid content (51.48mg/100 ml), and total antioxidant activity (72.24%). The overall acceptability of the fermented turmeric beverage reached a high 98.10%. Notably, the FTB exhibited significantly improved attributes such as astringency, flavor, taste, and overall acceptability when compared to the non-fermented turmeric beverage (NFTB), with statistical significance (P < 0.05).