Characterization of redox and salinity-tolerant alkaline protease from Bacillus halotolerans strain DS5

Comprehensive biochemical, molecular and structural characterization of subtilisin with fibrinolytic potential in bioprocessing

Enzyme deployment is proliferating extensively in industries owing to their environmentally friendly and easily degradable attributes. This article undertakes an exhaustive examination of wild subtilisin enzyme, covering purification, biochemical delineation, analytical techniques, and practical implementations. The purification methodology involved partial refinement, anionic exchange, and gel filtration chromatography, culminating in a purification factor of 3.406, corroborated by SDS-PAGE showcasing a molecular weight of ~ 42 kDa. Biochemical scrutiny unveiled the enzyme's response, with an optimal pH at 9 and temperature peak at 60 ℃. Various surfactants, metal ions, organic solvents and inhibitors exhibited notable efficacy. Substrate specificity and kinetics showcased the utmost specificity with N-Suc-F-A-A-F-pNA, registering Km and Vmax values of 0.731 ± 0.5 mM and 0.87 ± 9 × 103 U/mg, respectively. Different bioanalytical techniquesproffered insights into structural and biophysical facets. Practical applications encompassed goat skin depilation, feather disintegration, blood clot dissolution, exemplifying the enzyme's multifaceted utility. To embark upon the elucidation of structure-function relationships, a three-dimensional model was devised through homology modelling, leveraging existing subtilisin structures (PDB: 3WHI). Molecular docking score of - 8.8 kcal/mol and dynamic simulations augmented the comprehension of molecular interactions with N-Suc-F-A-A-F-pNA. This research significantly contributes to unravelling the biochemical intricacies of wild subtilisin and underscores potential industrial and biomedical prowess. Subtilisin can be explored for its thrombolytic potential in several cardiovascular diseases. It may aid in the management of thrombosis by dissolving blood clots in conditions like deep pulmonary embolism, myocardial infarction, ischemic strokes, and in atherosclerosis by breaking down fibrin in arterial plaques, thus preventing heart attacks and strokes.

Redox and solvent-stable alkaline serine protease from Bacillus patagoniensis DB-5: heterologous expression, properties, and biotechnological applications

The aprBP gene from Bacillus patagoniensis DB-5, encoding a 378-amino-acid alkaline protease, was cloned and expressed in Escherichia coli. The amino acid sequence of APrBP showed 62.8-84.4% identity with the S8 peptidase subtilisin family alkaline proteases reported in the literature. Recombinant APrBP was purified using Ni-NTA affinity chromatography with 45.61% recovery and a homogeneous band was detected at approximately 38 kDa on the SDS-PAGE gel. The optimum temperature of APrBP was 60°C. The presence of 2 mM Ca2+ significantly enhanced the optimal temperature and thermostability. The enzyme demonstrated optimum activity at pH 12 and maintained high stability at pH 8.0-11.0. Protease activity was stimulated by Mn2+, Ca2+, Mg2+, Ni2+, TritonX-100, Tween-20 and Tween-80, while completely inactivated by PMSF, EDTA and Cu2+. The APrBP exhibited good tolerance to oxidizing and reducing agents. Notably, the protease exhibited remarkable stability in 50% (v/v) concentrations of several organic solvents, such as methanol, acetone, glycerol, dimethyl sulfoxide, n-hexane, and ethyl acetate. The APrBP efficiently hydrolyzed natural proteins, demonstrating the highest catalytic efficiency for casein, excellent hydrolysis activity for bovine serum albumin, hemoglobin, and keratin, and favorable hydrolysis ability for whey proteins. Moreover, molecular docking results revealed stable interactions between APrBP and casein, hemoglobin, whey proteins and keratin. This study indicated that APrBP has some useful properties and explored its potential as a bio-additive detergent as well as in utilizing feather waste and whey protein.

Enhanced Synthesis, Purification, and Characterization of a Marine Bacterial Consortium-Derived Protease Enzyme With Destaining and Keratinolytic Activity

Two marine-derived bacteria, Bacillus paralicheniformis (HR-1) and Bacillus haynesii (HR-5), were isolated from sediments and identified using 16S ribosomal RNA gene amplification and sequencing as well as biochemical analysis. The development of a bacterial consortium (HR-1 & HR-5) from these two bacteria was used to increase the production of the protease enzyme under various conditions, including fermentation media, carbon and nitrogen sources (1% w/v), different pH levels, incubation time, and the obtained enzyme, were detected using SDS-PAGE followed by purification. Bacterial consortium HR-1 & HR-5 exhibited maximum protease production (330.42 ± 4.47 U/mL) than the individual isolates HR-1 (156.32 ± 2.14 U/mL) and HR-5 (185.73 ± 5.14 U/mL) on supplementing peptone (1% w/v), 2.8% skim milk + N-broth, pH 9, and dextrose (1% w/v) after 48 h of incubation time. The purified enzyme showed increased activity at alkaline pH 9.0 and also in the presence of ions such as Ca+2, Fe+3, Mg+2, and Mn+2. The purified protease obtained from the consortium HR-1 and HR-5 shows improved efficiency for stain removal from cloth as well as high keratinolytic efficiency for poultry feather degradation, making this enzyme suitable for industrial use, particularly in the textile and tannery sectors.

Starter molds and multi-enzyme catalysis in koji fermentation of soy sauce brewing: A review

Soy sauce is a traditional fermented food produced from soybean and wheat under the action of microorganisms. The soy sauce brewing process mainly involves two steps, namely koji fermentation and moromi fermentation. In the koji fermentation process, enzymes from starter molds, such as protease, aminopeptidase, carboxypeptidase, l-glutaminase, amylase, and cellulase, hydrolyze the protein and starch in the raw ingredients to produce short-chain substances. However, the enzymatic reactions may be diminished after being subjected to moromi fermentation due to its high NaCl concentration. These enzymatically hydrolyzed products are further metabolized by lactic acid bacteria and yeasts during the moromi fermentation process into organic acids and aromatic compounds, giving soy sauce a unique flavor. Thus, the starter molds, such as Aspergillus oryzae, Aspergillus sojae, and Aspergillus niger, and their secreted enzymes play crucial roles in soy sauce brewing. This review comprehensively covers the characteristics of the starter molds mainly used in soy sauce brewing, the enzymes produced by starter molds, and the roles of enzymes in the degradation of raw material. We also enumerate current problems in the production of soy sauce, aiming to offer some directions for the improvement of soy sauce taste.