Statistical Approach for Optimization of Physiochemical Requirements on Alkaline Protease Production from Bacillus licheniformis NCIM 2042

Identification, characterization and optimization of culture medium conditions for organic acid-producing lactic acid bacteria strains from Chinese fermented vegetables

Lactic acid bacteria (LAB) are widely exploited in fermented foods and are gaining attention for novel uses due to their safety as biopreservatives. In this study, several organic acid-producing LAB strains were isolated from fermented vegetables for their potential application in fermentation. We identified nine novel strains belonging to four genera and five species, Lactobacillus plantarum PC1-1, YCI-2 (8), YC1-1-4B, YC1-4 (4), and YC2-9, Lactobacillus buchneri PC-C1, Pediococcus pentosaceus PC2-1 (F2), Weissella hellenica PC1A, and Enterococcus sp. YC2-6. Based on the results of organic acids, acidification, growth rate, antibiotic activity and antimicrobial inhibition, PC1-1, YC1-1-4B, PC2-1(F2), and PC-C1 showed exceptional biopreservative potential. Additionally, PC-C1, YC1-1-4B, and PC2-1(F2) recorded higher (p < 0.05) growth by utilizing lower concentrations of glucose (20 g/L) and soy peptone (10 g/L) as carbon and nitrogen sources in optimized culture conditions (pH 6, temperature 32 °C, and agitation speed 180 rpm) at 24hr and acidification until 72hr in batch fermentation, which suggests their application as starter cultures in industrial fermentation.

Alkaline Protease Production from Bacillus gibsonii 6BS15-4 Using Dairy Effluent and Its Characterization as a Laundry Detergent Additive

Protease is a widely used enzyme particularly in the detergent industry. In this research, we aimed to isolate alkaline protease-producing bacteria for characterization as a laundry detergent additive. The screening of alkaline protease production was investigated on basal medium agar plus 1% skim milk at pH 11, with incubation at 30°C. The highest alkaline protease-producing bacterium was 6BS15-4 strain, identified as Bacillus gibsonii by 16S rRNA gene sequencing. While the optimum pH was 12.0, the strain was stable at pH range 7.0-12.0 when incubated at 45°C for 60 min. The alkaline protease produced by B. gibsonii 6BS15-4 using dairy effluent was characterized. The optimum temperature was 60°C and the enzyme was stable at 55°C when incubated at pH 11.0 for 60 min. Metal ions K+, Mg2+, Cu2+, Na+, and Zn2+ exhibited a slightly stimulatory effect on enzyme activity. The enzyme retained over 80% of its activity in the presence of Ca2+, Ba2+, and Mn2+. Thiol reagent and ethylenediaminetetraacetic acid did not inhibit the enzyme activity, whereas phenylmethylsulfonyl fluoride significantly inhibited the protease activity. The alkaline protease from B. gibsonii 6BS15-4 demonstrated efficiency in blood stain removal and could therefore be used as a detergent additive, with potential for various other industrial applications.

Optimization of protease production by Bacillus cereus HMRSC30 for simultaneous extraction of chitin from shrimp shell with value-added recovered products

Chitin extraction from shrimp shell powder (SSP) using protease-producing microbes is an attractive approach for valorizing shrimp shell waste because it is simple and environmentally friendly. In this study, the protease production and chitin extraction from SSP by Bacillus cereus HMRSC30 were simultaneously optimized using statistical approaches. As a result, fermentation in medium composed of 30 g/L SSP, 0.2 g/L MgSO₄ · 7H₂O, 3 g/L (NH₄)₂SO₄, 0.5 g/L K₂HPO₄, and 1.5 g/L KH₂PO₄ (pH 6.5) for 7 days maximized protease production (197.75 ± 0.33 U/mL) to approximately 1.64-fold compared to unoptimized condition (126.8 ± 0.047 U/mL). This level of enzyme production was enough to achieve 97.42 ± 0.28% deproteinization (DP) but low demineralization (DM) of 53.76 ± 0.21%. The high DM of 90% could be easily accomplished with the post-treatment using 0.4 M HCl and acetic acid. In addition, the study evaluated the possible roadmap to maximize the value of generated products and obtain additional profits from this microbial process. The observation showed the possibility of serving crude chitin as a bio-adsorbent with the highest removal capacity against Coomassie brilliant blue (97.99%), followed by methylene blue (74.42%). The recovered protease exhibited the function to remove egg yolk stain, indicating its potential for use as a detergent in de-staining. The results corroborated the benefits of microbial fermentation by B. cereus HMRSC30 as green process for comprehensive utilization of shrimp shell waste as well as minimizing waste generation along the established process.

Proteomic analysis and optimized production of Alkalihalobacillus patagoniensis PAT 05T extracellular proteases

Extracellular proteolytic extracts from the haloalkalitolerant strain Alkalihalobacillus patagoniensis PAT 05^T have proved highly efficient to reduce wool felting, as part of an ecofriendly treatment suitable for organic wool. In the present study, we identified the extracellular proteases produced by PAT 05^T and we optimized its growth conditions for protease production through statistical methods. A total of 191 proteins were identified in PAT 05^T culture supernatants through mass spectrometry analysis. Three of the 6 detected extracellular proteases belonged to the serine-endopeptidase family S8 (EC 3.4.21); two of them showed 86.3 and 67.9% identity with an alkaline protease from Bacillus alcalophilus and another one showed 50.4% identity with Bacillopeptidase F. The other 3 proteases exhibited 55.3, 49.4 and 61.1% identity with D-alanyl-D-alanine carboxypeptidase DacF, D-alanyl-D-alanine carboxypeptidase DacC and endopeptidase LytE, respectively. Using a Fractional Factorial Design followed by a Central Composite Design optimization, a twofold increase in protease production was reached. NaCl concentration was the most influential factor on protease production. The usefulness of PAT 05^T extracellular proteolytic extracts to reduce wool felting was possible associated with the activity of the serine-endopeptidases closely related to highly alkaline keratinolytic proteases. The other identified proteases could cooperate, improving protein hydrolysis. This study provided valuable information for the exploitation of PAT 05^T proteases which have potential for the valorization of organic wool as well as for other industrial applications.

Enhanced catalytic activity of Bacillus aryabhattai P1 protease by modulation with nanoactivator

In the developing area of modern nanobiotechnology, the research is being focused on enhancement of catalytic performance in terms of efficiency and stability of enzymes to fulfill the industrial demand. In the context of this interdisciplinary era, we isolated and identified alkaline protease producer Bacillus aryabhattai P1 by polyphasic approach and then followed one variable at a time approach to optimize protease production from P1. The modified components of fermentation medium (g/L) were wheat bran 10, soybean flour 10, yeast extract 5, NaCl 10, KH₂PO₄ 1, K₂HPO₄ 1 and MgSO₄·7H₂O 0.2 (pH 9). The optimum alkaline protease production from P1 was recorded 75 ± 3 U/mg at 35 °C and pH 9 after 96 h of fermentation period. Molecular weight of partially purified P1 alkaline protease was 26 KDa as revealed by SDS-PAGE. Calcium based nanoceramic material was prepared by wet chemical precipitation method and doped in native P1 protease for catalytic activity enhancement. Catalytic activity of modified P1 protease was attained by nanoactivator mediated modulation was more by 5.58 fold at pH 10 and 30 °C temperature. The nanoceramic material named as nanoactivator, with grain size of 40–60 nm was suitable to redesign the active site of P1 protease. Such types of modified proteases can be used in different nanobiotechnological applications.

Statistical optimisation of protease production using a freshwater bacterium Chryseobacterium cucumeris SARJS-2 for multiple industrial applications

Feathers, rich in keratin, are usually the unused by-products of poultry industries. In addition, the cast-off X-ray films serve as secondary sources of silver, and the traditional method of silver extraction from this source is costly and not eco-friendly. Therefore, the current study focuses on protease production using a freshwater bacterium Chryseobacterium cucumeris SARJS-2, aiming to convert these wastes into useful products. The protease production was optimized by one-factor-at-a-time (OFAT), followed by Plackett Burman design (PBD) and response surface methodology (RSM). The protease production got enhanced by more than two folds after the statistical optimisation. Upon partial purification, the enzyme activity increased by approximately three folds. The protease was active in the range of temperatures from 25 to 75 °C, but the optimum temperature was recorded as 35 °C. The protease exhibited detergent compatibility and organic solvent stability. The detergent compatibility suggests the protease could be a detergent additive. It was also found that the presence of Fe⁺² enhanced protease activity. The protease was tested for stain removal, feather degradation and silver recovery applications. It was found that the protease could efficiently remove stains of blood and tomato sauce. In addition, the protease was found to be a successful candidate for feather degradation, thereby feather-hydrolysate production which has prominent roles as nature-friendly fertilizer and animal feed ingredient. The protease also degraded gelatin from the X-ray films to release the silver-halides for silver recovery. The results recommend that the SARJS-2 protease is a potential candidate for use in eco-friendly applications in various industrial sectors.

A novel DNA methylation motif identified in Bacillus pumilus BA06 and possible roles in the regulation of gene expression

Single-molecule real-time (SMRT) sequencing can be used to identify a wide variety of chemical modifications of the genome, such as methylation. Here, we applied this approach to identify N6-methyl-adenine (m6A) and N4-methyl-cytosine (m4C) modification in the genome of Bacillus pumilus BA06. A typical methylation recognition motif of the type I restriction-modification system (R-M), 5'-TC^m6AN8TTGG-3'/3'-AGTN8^m6AACC-5', was identified. We confirmed that this motif was a new type I methylation site using REBASE analysis and that it was recognized by a type I R-M system, Bpu6ORFCP, according to methylation sensitivity assays in vivo and vitro. Furthermore, we found that deletion of the R-M system Bpu6ORFCP induced transcriptional changes in many genes and led to increased gene expression in pathways related to ABC transporters, sulfur metabolism, ribosomes, cysteine and methionine metabolism and starch and sucrose metabolism, suggesting that the R-M system in B. pumilus BA06 has other significant biological functions beyond protecting the B. pumilus BA06 genome from foreign DNA.

Optimization, isolation, characterization and hepatoprotective effect of a novel pigment-protein complex (phycocyanin) producing microalga: Phormidium versicolorNCC-466 using response surface methodology

In our study, we focused on the optimization; antioxidant and hepatoprotective potentials of novel pigment-protein complex(C-PC) isolated from Phormidium versicolor against cadmium induced liver injury in rats. From analysis, the C-PC extraction parameters were optimized using the response surface methodology (RSM) for optimal recoveries of C-PC extraction. For analysis, the optimum operational conditions for maximizing phycocyanins concentration (67.45mg/g DM) were found to be water/solid 2, temperature 32.5°C and pH7.2.This pigment was identified using HPLC and FTIR analysis. In addition, the molecular masses of α and β subunits were 17 and 19kDa. Scavenging activity of superoxide anion, hydroxyl, nitric oxide radicals and metal chelating in vitro results indicated that C-PC has an excellent capacity as antioxidant. In vivo study, C-PC significantly prevented cadmium-induced elevation of ALAT, ASAT and bilirubin levels in rats. The histopathological observations supported the results serum enzymes assays. The results of this study revealed that C-PC has significant hepatoprotective potential. C-PC (50mgkg^-1 body weight) significantly enhanced the levels of antioxidant enzymes. It can be concluded that C-PC possesses prevention action against hepatotoxicity caused by cadmium.

Production optimization of a heat-tolerant alkaline pectinase from Bacillus subtilis ZGL14 and its purification and characterization

Alkaline pectinase has important applications in the pretreatment of waste water from food processing and in both the fabric and paper industries. In this study, a 2-level factorial design was used to screen significant factors that affect the activity of alkaline pectinase, and the response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize their concentrations. Starch, peptone, KH₂PO₄ and K₂HPO₄·3H₂O were found to significantly affect the activity of alkaline pectinase. Their optimal concentrations were as follows: 4.68% starch, 1.6% peptone, 0.26% KH₂PO₄ and 0.68% K₂HPO₄·3H₂O. Under the above conditions, the activity of alkaline pectinase was significantly improved to 734.11 U/mL. Alkaline pectinase was purified to homogeneity with a recovery rate of 9.6% and a specific activity of 52372.52 U/mg. Its optimal temperature and pH were 50°C and 8.6, respectively. The purified enzyme showed strong thermo-stability and good alkali resistance. In addition, the activity of alkaline pectinase was improved in the presence of Mg²⁺. Cu²⁺, Mn²⁺, and Co²⁺ significantly inhibited its activity. This study provides an important basis for the future development and use of a heat-tolerant alkaline pectinase from B. subtilis ZGL14.

Novel Sequential Screening and Enhanced Production of Fibrinolytic Enzyme by Bacillus sp. IND12 Using Response Surface Methodology in Solid-State Fermentation

Fibrinolytic enzymes have wide applications in clinical and waste treatment. Bacterial isolates were screened for fibrinolytic enzyme producing ability by skimmed milk agar plate using bromocresol green dye, fibrin plate method, zymography analysis, and goat blood clot lysis. After these sequential screenings, Bacillus sp. IND12 was selected for fibrinolytic enzyme production. Bacillus sp. IND12 effectively used cow dung for its growth and enzyme production (687 ± 6.5 U/g substrate). Further, the optimum bioprocess parameters were found out for maximum fibrinolytic enzyme production using cow dung as a low cost substrate under solid-state fermentation. Two-level full-factorial experiments revealed that moisture, pH, sucrose, peptone, and MgSO₄ were the vital parameters with statistical significance (p < 0.001). Three factors (moisture, sucrose, and MgSO₄) were further studied through experiments of central composite rotational design and response surface methodology. Enzyme production of optimized medium showed 4143 ± 12.31 U/g material, which was more than fourfold the initial enzyme production (978 ± 36.4 U/g). The analysis of variance showed that the developed response surface model was highly significant (p < 0.001). The fibrinolytic enzyme digested goat blood clot (100%), chicken skin (83 ± 3.6%), egg white (100%), and bovine serum albumin (29 ± 4.9%).

Optimization of physical and morphological regime for improved cellulase free xylanase production by fed batch fermentation using Aspergillus niger (KP874102.1) and its application in bio-bleaching

The physiological and morphological changes were extensively studied during fed batch fermentation using newly isolated Aspergillus niger (KP874102.1). Significantly higher xylanase production was possible through optimization of environmental stresses by fed batch process. The fed batch fermentation was carried out for improved xylanase production (2524 U) where initial xylan was kept 1.5 g/L in the production medium. However, 3 g/L of xylan with 50 mM K₂HPO₄ having pH-7 was consecutively fed at 72 and 120 h of fermentation. K₂HPO₄ showed significant role both the morphology of the microorganism and produces enzymes in fed batch fermentation. During feeding phase, the pH was found in the range of 6.5 to 7 which was used as marker for the fed batch process. The crude enzyme was used for the bio-bleaching of banana pulp.

Production and biochemical characterization of an alkaline protease from Aspergillus oryzae CH93

In this study, Aspergillus oryzae CH93 was isolated from soil sample and examined using molecular analysis. Following culture of A. oryzae CH93 under optimal enzyme production, a 47.5kDa extracellular protease was purified using ammonium sulfate precipitation and Q-Sepharose chromatography. The optimal pH 8 and temperature of 50°C obtained for the isolated protease. Sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTAB), H₂O₂ decreased activity, while Triton X-100 and phenylmethanesulfonyl fluoride (PMSF) had no inhibitory effect on the enzyme activity; meanwhile, 2-mercaptoethanol and ethylenediaminetetraacetic acid (EDTA) declined the protease activity. Isoamyl alcohol and acetone (30%) enhanced activity whereas 2-propanol, isopropanol and dimethyl sulfoxide (DMSO) (30%) reduced protease activity. The enzyme exhibited a half-life of 100min at its optimum temperature. Among five substrates of bovine serum albumin (BSA), N-acetyl-l-tyrosine ethyl ester monohydrate (ATEE), casein, azocasein and gelatin results showed that casein is the best substrate with V_max of 0.1411±0.004μg/min and K_m of 2.432±0.266μg/ml. In conclusion, the extracted protease from A. oryzae CH93 as a fungal source possessed biochemical features which could be useful in some application usages.

Enhanced production of protease by Pseudoalteromonas arctica PAMC 21717 via statistical optimization of mineral components and fed-batch fermentation

The objective of this study was to statistically optimize the mineral components of the nutritional medium required for enhancing the production of a cold-active extracellular serine-type protease, W-Pro21717, by the Antarctic bacterium Pseudoalteromonas arctica PAMC 21717. Skim milk was identified as the major efficient inducer. Among the 12 components included in the unoptimized medium, skim milk, NaCl, Na2SO4, Fe(C6H5O7) (ferric citrate), and KCl were determined, by the Plackett-Burman and Box-Behnken design, to have a major effect on W-Pro21717 production. Fed-batch fermentation (5 L scale) using the mineral-optimized medium supplemented with concentrated skim milk (critical medium component) resulted in a W-Pro21717 activity of 53.4 U/L, a 15-fold increment in production over that obtained using unoptimized flask culture conditions. These findings could be applied to scale up the production of cold-active protease.

Thermotolerant alkaline protease enzyme from Bacillus licheniformis A10: purification, characterization, effects of surfactants and organic solvents

In this study, the extracellular thermostable alkaline protease out of A10 strain was purified 1.38-fold with 9.44% efficiency through the ammonium sulfate precipitation-dialysis and DE52 anion exchange chromatography methods. The molecular weight of the enzyme in question along with sodium dodecyl sulfate-polyacrylamide gel electrophoresis was determined to be approximately 40.55 kDa, whereas the optimum pH and temperature ratings were identified as 9.0 and 70 °C, respectively. It was seen that the enzyme had remained stable between pH 7.5-10.5 range, protecting more than 90% of its activity in the wake of 1 h incubation at 60-70 °C. It was also observed that the enzyme enhanced its activity in the presence of Mg(2+), Mn(2+), K(+), while Fe(2+), Ni(2+), Zn(2+), Ag(+ )and Co(2+ ) decreased the activity. Ca(2+), however, did not cause any change in the activity. The enzyme was seen to have been totally inhibited by phenylmethylsulfonyl fluoride, therefore, proved to be a serine alkaline protease.