An alkaline proteinase of an alkalophilicBacillus sp

Partitioning purification, biochemical characterization, and milk coagulation efficiency of protease from a newly Streptomyces sp. isolate

An actinobacteria strain was isolated from an olive waste mill and tested for protease production on skimmed milk media. The strain identification was achieved through both 16 S rDNA sequencing and phenotypic characterization. The enzyme was purified using the ammonium sulfate/t-butanol three-phase partitioning (TPP) method, followed by characterization to investigate the effect of pH, temperature, and various chemical agents. Subsequently, the enzyme was assessed for its milk coagulation activity. The strain belonging to the Streptomyces genera, exhibits significant phylogenetic and phenotypic differences from the aligned species, suggesting its novelty as a new strain. The enzyme was best separated in the TPP aqueous phase with a 5.35 fold and 56.25% yield. Optimal activity was observed at pH 9.0 and 60 °C, with more than half of the activity retained within the pH range of 7-10 over one hour. The protease demonstrated complete stability between 30 and 60 °C. While metallic ions enhanced enzyme activity, EDTA acted as an inhibitor. The enzyme displayed resistance to H2O2, SDS, Tween 80, and Triton X-100. Notably, it was activated in organic solvents (ethyl acetate, petroleum ether, and xylene), maintaining > 75% of its original activity in butanol, ethanol, and methanol. Additionally, the enzyme yielded high milk coagulant activity of 11,478 SU/mL. The new Streptomyces sp. protease revealed high activity and stability under a wide range of biochemical conditions. Its use in the dairy industry appears particularly promising. Further industrial process investigations will be valuable in determining potential uses for this enzyme.

Bacillus siamensis 3BS12-4 Extracellular Compounds as a Potential Biological Control Agent against Aspergillus flavus

Aspergillus flavus, the primary mold that causes food spoilage, poses significant health and economic problems worldwide. Eliminating A. flavus growth is essential to ensure the safety of agricultural products, and extracellular compounds (ECCs) produced by Bacillus spp. have been demonstrated to inhibit the growth of this pathogen. In this study, we aimed to identify microorganisms efficient at inhibiting A. flavus growth and degrading aflatoxin B1. We isolated microorganisms from soil samples using a culture medium containing coumarin (CM medium) as the sole carbon source. Of the 498 isolates grown on CM medium, only 132 bacterial strains were capable of inhibiting A. flavus growth. Isolate 3BS12-4, identified as Bacillus siamensis, exhibited the highest antifungal activity with an inhibition ratio of 43.10%, and was therefore selected for further studies. The inhibition of A. flavus by isolate 3BS12-4 was predominantly attributed to ECCs, with a minimum inhibitory concentration and minimum fungicidal concentration of 0.512 g/ml. SEM analysis revealed that the ECCs disrupted the mycelium of A. flavus. The hydrolytic enzyme activity of the ECCs was assessed by protease, β-1,3-glucanase, and chitinase activity. Our results demonstrate a remarkable 96.11% aflatoxin B1 degradation mediated by ECCs produced by isolate 3BS12-4. Furthermore, treatment with these compounds resulted in a significant 97.93% inhibition of A. flavus growth on peanut seeds. These findings collectively present B. siamensis 3BS12-4 as a promising tool for developing environmentally friendly products to manage aflatoxin-producing fungi and contribute to the enhancement of agricultural product safety and food security.

Recycling of printed Xerographic paper using Aspergillus assiutensis enzyme cocktail: an integrated approach to sustainable development

To overcome the human and animal survivability risk, sustainable development is the only option on earth that can be achieved through the maximum use of renewable environmental resources. Recycling of waste paper is an emerging waste management approach to conserve natural resources. Herein, we studied enzyme-mediated process to recycle the xerographic paper by using the crude fungal extract from indigenously isolated fungi identified as Aspergillus assiutensis. The fungal enzyme cocktail has been characterized for the production of multiple enzymes namely cellulase, amylase, xylanase, pectinase, and protease. All these enzymes have pH optima in the acidic range and except cellulase and all the enzymes are stable from 10 to 80 C. In the zymogram analysis, pectinase, xylanase, amylase, and cellulase were detected at 68 kDa, ~ 54 kDa, 38 kDa, and 30 kDa, respectively. Also, the presence of protease was confirmed by the clear zone at 68, 31, and 16 kDa. A 26% decrease in the kappa number and reduction in Hex A of the pulp was observed on the treatment of the pulp with enzyme as compared to the control pulp without any treatment. The physical and chemical properties of the pulp were also improved by enzyme-mediated pulping as compared to the control The physiochemical parameter of the effluent like TDS was reduced (397 ppm) significantly in comparison to chemical deinking process and it was within the permissible limit. BOD and alkalinity were reduced when the enzymes and chemical dosage were used in combination. These results indicate that chemi-enzymatic deinking is most promising to reduce or remove the pollution parameters including ink and this approach can be used in the paper and pulp industry for sustainable development.

Immobilization of alkaline protease produced by Streptomyces rochei strain NAM-19 in solid state fermentation based on medium optimization using central composite design

This study evaluated Streptomyces rochei strain NAM-19 solid-state fermentation of agricultural wastes to produce alkaline protease. Alkaline protease production increased with flaxseed, rice bran, and cheese whey fermentation reaching 147 U/mL at 48 h. Statistical optimization of alkaline protease production was performed using the central composite design (CDD). Results of CDD and the optimization plot showed that 4.59 g/L flaxseed, 4.31 g/L rice bran, 4.17 mL cheese whey, and a vegetative inoculum size of 7.0% increased alkaline protease production by 27.2% reaching 186 U/mL. Using the 20-70% ammonium sulfate fractionation method, the optimally produced enzyme was partially purified to fivefold. The partially purified alkaline protease was then covalently immobilized on a biopolymer carrier, glutaraldehyde-polyethylene-imine-κ-carrageenan (GA-PEI-Carr), with 90% immobilization efficiency. Characterizations revealed that immobilization improved thermostability, reusability, optimum temperature, and sensitivity towards metal ions of the free enzyme. The optimal temperature for free and immobilized enzymes was 40 and 50 °C, respectively. Both enzymes had the same optimum pH of 10. Immobilization increased Km from 19.73 to 26.52 mM and Vmax from 56.7 to 62.5 mmol min-1L-1. The immobilized enzyme retained 35% of its initial activity at 70 °C, while the free enzyme retained only 5%. The immobilized enzyme kept 80% of its initial activity at the 20th cycle. After 7 weeks of storage, the free enzyme lost all its initial activity, whereas the immobilized enzyme retained 50%. The free and immobilized enzymes were able to hydrolyze gelatin, and azo-casein demonstrating different relative activity, 85, 80, 90 and 95%, respectively, compared to casein (100%).

Enzymatic Activity and Amino Acids Production of Predominant Fungi from Traditional Meju during Soybean Fermentation

To investigate the effect of the predominant fungal species from Korean traditional meju and doenjang on soybean fermentation, the enzymatic activity and amino acid production of twenty-two fungal strains were assessed through solid- and liquid-state soybean fermentation. Enzymatic activity analyses of solid-state fermented soybeans revealed different enzyme activities involving protease, leucine aminopeptidase (LAP), carboxypeptidase (CaP), glutaminase, γ-glutamyl transferase (GGT), and amylase, depending on the fungal species. These enzymatic activities significantly affected the amino acid profile throughout liquid-state fermentation. Strains belonging to Mucoromycota, including Lichtheimia, Mucor, Rhizomucor, and Rhizopus, produced smaller amounts of total amino acids and umami-producing amino acids, such as glutamic acid and aspartic acid, than strains belonging to Aspergillus subgenus circumdati. The genera Penicillium and Scopulariopsis produced large amounts of total amino acids and glutamic acid, suggesting that these genera play an essential role in producing umami and kokumi tastes in fermented soybean products. Strains belonging to Aspergillus subgenus circumdati, including A. oryzae, showed the highest amino acid content, including glutamic acid, suggesting the potential benefits of A. oryzae as a starter for soybean fermentation. This study showed the potential of traditional meju strains as starters for soybean fermentation. However, further analysis of processes such as the production of G-peptide for kokumi taste and volatile compounds for flavor and safety is needed.

Multifaceted plant growth-promoting traits of indigenous rhizospheric microbes against Phomopsis theae, a causal agent of stem canker in tea plants

Phomopsis canker is one of the major devastating stem diseases that occur in tea plants caused by the fungal pathogen Phomopsis theae. Rapid development of this disease leads to a capital loss in the tea industry which demands an ecofriendly disease management strategy to control this aggressive pathogen. A total of 245 isolates were recovered from the tea rhizosphere and screened for in vitro plant growth promoting (PGP) traits and antagonism against P. theae. Among them, twelve isolates exhibited multifarious PGP traits including phytohormones, siderophore, hydrogen cyanide, salicylic acid production, phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and antifungal activity. In vitro studies on morphological, biochemical, and phylogenetic analyses classified the selected isolates as Pseudomonas fluorescens (VPF5), Bacillus subtilis (VBS3), Streptomyces griseus (VSG4) and Trichoderma viride (VTV7). Specifically, P. fluorescens VPF5 and B. subtilis VBS3 strains showed the highest level of PGP activities. On the other hand, VBS3 and VTV7 strains showed higher biocontrol efficacy in inhibiting mycelia growth and spore germination of P. theae. A detailed investigation on hydrolytic enzymes produced by antagonistic strains, which degrade the fungus cell wall, revealed that highest amount of chitinase and β-1,3- glucanase in VTV7 and VBS3 strains. Further, the key antifungal secondary metabolites from these biocontrol agents associated with suppression of P. theae were identified using gas chromatography mass spectrometry. The above study clearly recognized the specific traits in the isolated microbes, which make them good candidates as plant growth-promoting rhizobacteria (PGPR) and biocontrol agents to improve plant growth and health. However, greenhouse trials and field application of these beneficial microbes is required to further confirm their efficacy for the management of stem canker in tea cultivation.

The escalated potential of the novel isolate Bacillus cereus NJD1 for effective biodegradation of LDPE films without pre-treatment

This study focused on the biodegradation of LDPE films using a novel isolate of Bacillus obtained from soil samples collected from a 20-year-old plastic waste dump. The aim was to evaluate the biodegradability of LDPE films treated with this bacterial isolate. The results indicated a 43% weight loss of LDPE films within 120 days of treatment. The biodegradability of LDPE films was confirmed through various testing methods, including BATH, FDA, CO₂ evolution tests, and changes in total cell growth count, protein content, viability, p^H of the medium, and release of microplastics. The bacterial enzymes, including laccases, lipases, and proteases, were also identified. SEM analysis revealed biofilm formation and surface changes in treated LDPE films, while EDAX analysis showed a reduction in carbon elements. AFM analysis demonstrated differences in roughness compared to the control. Furthermore, wettability increased and tensile strength decreased, confirming the biodegradation of the isolate. FTIR spectral analysis showed changes in skeletal vibrations, such as stretches and bends, in the linear structure of polyethylene. FTIR imaging and GC-MS analysis also confirmed the biodegradation of LDPE films by the novel isolate identified as Bacillus cereus strain NJD1. The study highlights the potentiality of the bacterial isolate for safe and effective microbial remediation of LDPE films.

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.

Green method for improving performance attributes of wool fibres using immobilized proteolytic thermozyme

Wool has the tendency to turn into felt during agitation in washing machines. Thus, a benign non-polluting method for the production of machine-washable wool was developed herein. Initially, a proteolytic bacteria was isolated from hot region soil. The bacterial isolate was identified as Bacillus safensis FO-36bMZ836779 according to the 16S rRNA gene sequencing. Afterwards, the extracellular protease produced by this isolate was covalently immobilized in order to enhance its stability under non-ambient conditions which are usually adopted in industrial sectors like textile industries. Sericin, which is usually discharged into degumming effluent of natural silk, was utilized to prepare the immobilization carrier. Box–Behnken design was adopted in order to hone the preparation of the sericin–polyethylene–imine–glutaraldehyde activated agar carrier. The pH and temperature profiles of the free and immobilized proteases were compared. Later, wool fibres were bio-treated with both the free and the immobilized enzymes. The effect of process conditions on the resistance of the bio-finished wool to felting was investigated. The alteration in the fibre morphology was monitored using SEM. Amino acid analysis and alkali solubility tests were adopted to assign any change in the chemical structure of the bio-treated wool. The influence of bio-treatment of wool on its inherent properties was assigned. Results revealed that bio-treatment of wool with the said enzyme led to production of machine-washable wool without severe deterioration in the fibres’ properties. In an energy- and water-consuming process, the hot solution from bio-treatment bath was used successfully in dyeing of wool.

Phylogenetic survey of the subtilase family and a data-mining-based search for new subtilisins from Bacillaceae

The subtilase family (S8), a member of the clan SB of serine proteases are ubiquitous in all kingdoms of life and fulfil different physiological functions. Subtilases are divided in several groups and especially subtilisins are of interest as they are used in various industrial sectors. Therefore, we searched for new subtilisin sequences of the family Bacillaceae using a data mining approach. The obtained 1,400 sequences were phylogenetically classified in the context of the subtilase family. This required an updated comprehensive overview of the different groups within this family. To fill this gap, we conducted a phylogenetic survey of the S8 family with characterised holotypes derived from the MEROPS database. The analysis revealed the presence of eight previously uncharacterised groups and 13 subgroups within the S8 family. The sequences that emerged from the data mining with the set filter parameters were mainly assigned to the subtilisin subgroups of true subtilisins, high-alkaline subtilisins, and phylogenetically intermediate subtilisins and represent an excellent source for new subtilisin candidates.

Seed-Borne Probiotic Yeasts Foster Plant Growth and Elicit Health Protection in Black Gram (Vigna mungo L.)

Black gram is one of the most indispensable components of the world food basket and the growth and health of the crop get influenced by biotic and abiotic factors. Beneficial phyto-microbes are one among them that influence the crop growth, more particularly the seed borne microbes are comparatively beneficial, that they pass from generation to generation and are associated with the plants from establishment to development. In the present study, twenty seed-borne yeasts were characterized and tested for growth promotion of black gram and their antagonism against black gram phytopathogens. Two yeasts, Pichia kudriavzevii POY5 and Issatchenkia terricola GRY4, produced indole acetic acid (IAA), siderophore, 1-amino cyclopropane-1-carboxylic acid deaminase (ACCD), and plant defense enzymes. They solubilized phosphate and zinc and fixed atmospheric nitrogen. Inoculation of these two yeast isolates and Rhizobium BMBS1 improved the seed germination, physiological parameters and yield of black gram. Inoculation of Rhizoctonia solani-challenged plants with plant growth-promoting yeasts, resulted in the synthesis of defense-related enzymes such as peroxidases (POD), chitinases, catalase (CAT), and polyphenol oxidases (PPO). Thus, the seed-borne yeasts, Pichia kudriavzevii POY5 and Issatchenkia terricola GRY4, could be used as plant probiotics for black gram.

An insight of anopheline larvicidal mechanism of Trichoderma asperellum (TaspSKGN2)

Anopheline larvicidal property of T. asperellum has been found recently in medical science. The mechanism of actions exhibited by T. asperellum to infect mosquito larvae is the pivotal context of our present study. To infect an insect, entomopathogens must undergo some events of pathogenesis. We performed some experiments to find out the mechanisms of action of T. asperellum against anopheline larvae and compared its actions with other two well recognized entomopathogens like Metarhizium anisopliae and Beauveria bassiana. The methodology adopted for this includes Compound light and SE Microscopic study of host-pathogen interaction, detection of fungal spore adhesion on larval surface (Mucilage assay), detection of cuticle degrading enzymes (Spore bound pr1, chitinase and protease) by spectro-photometric method, Quantitative estimation of chitinase and protease enzymes, and determination of nuclear degeneration of hemocyte cells of ME (methanolic extract) treated larvae by T. asperellum under fluorescence microscope. Compound light microscopic studies showed spore attachment, appressorium and germ tube formation, invasion and proliferated hyphal growth of T. asperellum on epicuticle and inside of dead larvae. SEM study also supported them. After 3 h of interaction, spores were found to be attached on larval surface exhibiting pink colored outer layer at the site of attachment indicating the presence of mucilage surrounding the attached spores. The enzymatic cleavage of the 4-nitroanilide substrate yields 4-nitroaniline which indicates the presence of spore-bound PR1 protein (Pathogenecity Related 1 Protein) and it was highest (absorbance 1.298 ± 0.002) for T. asperellum in comparison with control and other two entomopathogens. T. asperellum exhibited highest enzymatic index values for both chitinase (5.20) and protease (2.77) among three entomopathogens. Quantitative experiment showed that chitinase enzyme concentration of T. asperellum (245 µg mL^-1) was better than other two M. anisopliae (134.59 µg mL^-1) and B. bassiana (128.65 µg mL^-1). Similarly protease enzyme concentration of this fungus was best (298.652 µg mL^-1) among three entomopathogens. Here we have detected and estimated fragmentized nuclei of hemocyte cells by fluorescence microscopy in treated larvae with different ME doses of T. asperellum, and also observed that mosquito larvae exposed to 0.1 mg mL^-1 dose of ME showed maximum (100%) nuclear fragmentations of hemocytes and while 20, 45, 70 and 85% of nuclear deformities were recorded at 0.02, 0.04, 0.06 and 0.08 mg mL^-1 concentrations of ME. The knowledge of this work certainly will help in understanding of mechanism of action of T. asperellum for anopheline larval killing and consequently in eradication of malaria vector.

Enhancing food waste biodegradation rate in a food waste biodigester with the synergistic action of hydrolase-producing Bacillus paralicheniformis GRA2 and Bacillus velezensis TAP5 co-culture inoculation

Food waste (FW) minimization at the source by using food waste biodigester (FWBs) has a vast potential to lower down the impact of increasing organic fraction in municipal solid waste generation. To this end, this research sought to check the performance of locally isolated hydrolase-producing bacteria (HPB) to improve food waste biodegradation rate. Two under-explored HPB identified as Bacillus paralicheniformis GRA2 and Bacillus velezensis TAP5 were able to produce maximum amylase, cellulase, protease and lipase activities, and demonstrated a significant hydrolase synergy in co-culture fermentation. In vitro biodegradation analysis of both autoclaved and non-autoclaved FW revealed that the HPB inoculation was effective to degrade total solids (>62%), protein (>19%), total fat (>51), total sugar (>86%), reducing sugar (>38%) and starch (>50%) after 8-day incubation. All co-culture treatments were recorded superior to the respective monocultures and the uninoculated control. The results of FW biodegradation using batch-biodigester trial indicated that the 1500 mL and 1000 mL inoculum size of HPB inoculant reached a plateau on the 4th day, with gross biodegradation percentage (GBP) of >85% as compared to control (66.4%). The 1000 mL inoculum was sufficient to achieve the maximum GBP (>90%) of FW after an 8-day biodigestion in a FWB.

Ficus palmata FORSKåL (BELES ADGI) as a source of milk clotting agent: a preliminary research

Objective

The demand for cheese, the insufficient supply and high cost of rennet, and the ethical issues of harvesting rennet oblige us to search for suitable alternatives of finding new proteases from plants. Ficus palmata Forskål (Moraceae) is one of the plants producing a protease called ficin that coagulates fresh milk. This study aims to study the milk coagulating abilities of bark, leaf, and stem powders of F. palmata Forskål.

Results

Stem powder has yielded better results. Chemical analyses of the powders have revealed that the percentage of crude protein of leaf, bark, and stem powders were 4.17, 7.39, and 16.26. This is an indication of the suitability of stem biomass as source of the enzyme of interest. Further research needs to aim at qualitative and quantitative analyses of milk-coagulating enzymes of F. palmata Forskål stem biomass to get new insights into industrial extraction of the enzymes of interest.

Characterization of a cold-active, detergent-stable metallopeptidase purified from Bacillus sp. S1DI 10 using Response Surface Methodology

The colder regions of Earth are inhabited by cold-adapted microorganisms designated as psychrophiles that are known to produce cold-active enzymes, such as peptidases, chaperones, lipases, cellulases, and phosphatases. These types of enzymes are a major part of the market of industrial enzymes. Bacteria isolated from water samples collected from the Chamba region in the Himalayas were screened for peptidase production using skim milk agar plates. Among the peptidase-producing bacteria isolated, 20% of the isolates exhibited fast growth and maximum zones of clearance, and thus, were used for further studies. The 16S rDNA sequence analysis of isolate S1DI 10 identified it as a Bacillus sp. The peptidase was cloned in pET28a vector and expressed in Escherichia coli BL21(DE3) and the His-tagged recombinant protein was purified using Ni-NTA column. The purified peptidase of SIDI 10 was found to be an alkaline, cold-active peptidase with optimal enzyme activity at 10°C and pH 8. An approach of one variable at a time was used to further study the effect of various metal ions, organic solvents and detergents on the peptidase enzyme. The peptidase activity was enhanced in the presence of Fe²⁺ and Mn²⁺ (metal ions), hexane (organic solvent), SDS- sodium dodecyl sulfate (anionic detergent) and Tween 80 (nonionic detergent). Response surface methodology (RSM) was used to determine the cumulative effect of these five variables. A 2⁵ full factorial central composite design was applied for the five independent variables to determine the optimal combinations of these constituents at the maximum peptidase activity.

Efficacy of silver nanoparticles against multidrug resistant clinical Staphylococcus aureus isolates from Nigeria

Multidrug resistant (MDR) S. aureus infections continue to account for excess mortality in hospital and community settings and constitute a rising global health problem. However, data on the efficacy and mechanism of actions of alternative solutions like silver nanoparticles in developing countries are lacking. This study investigated anti-staphylococcal activity of silver nanoparticles (AgNP) against local strains from Nigeria. A total 119 clinical isolates of S. aureus from five Nigerian laboratories categorized as MRSA (n = 52) and MSSA (n = 67) by PCR were studied. The MIC of AgNP produced by chemical reduction method and characterized by surface plasmon resonance absorbance and size equivalence by scanning electron microscopy was determined by microbroth dilution method. Its effect on protease activity and plasmids were also investigated. Baseline characteristics of the isolates revealed MDR phenotype of the isolates, carriage of diverse plasmids (15-32 kb) among the MDR MSSA, and mean extracellular protease activity of 24.8-55.7 U/mL. The chemically synthesized AgNP had a peak absorbance at 400 nm with a size equivalence of 4.58 nm. The MICs of AgNP against the isolates were 4.7 μg/mL and 4.9 μg/mL, respectively, for MRSA and MSSA (P > 0.05). The bactericidal effect of AgNP at 2.5-5 μg/mL on the MSSA and MRSA isolates was observed at 2.7-5.5 h post exposure in vitro. Further analysis revealed plasmid eviction in the MDR MSSA isolates exposed to 5 μg/mL AgNP and dose-dependent reduction in extracellular protease activity by 84.6-93.1%. Hemolysis of human erythrocytes by AgNP was not observed at the MIC range. Conclusion: This study revealed safety and efficacy of AgNP against clinical MDR S. aureus isolates from Nigeria, using plasmid eviction and protease inhibition as mechanisms of action.

Biotechnological potential of bacteria isolated from cattle environments of desert soils in Sonora Mexico

The aim of this research was to study the hydrolytic potential of bacteria isolated from cattle environments of two desert soils in one of the driest and hottest zones in America. A total of 26 points were sampled, 144 strains were isolated, and 50 strains were selected for the characterization of esterase, lipase, protease, and amylase activities and for 16S rRNA identification. Strains of the Bacillus, Pseudomonas, Acinetobacter, Enterobacter, Providencia, Escherichia, and Pantoea genera were identified. Comparisons of the proteolytic activity of the secretome from 14 strains (Bacillus n = 7, Escherichia n = 2; Providencia, Pseudomonas, Enterobacter, Pantoea and Acinetobacter n = 1) were performed. Four strains of Bacillus showed the highest proteolytic activity. These strains were characterized through a comparative analysis of pH and temperature as well as the effects of salt concentration on protease activity. Maximum proteolytic activity occurred in the range of pH 7-9 and temperatures between 50 and 70 °C for B. subtilis WD01, B. tequilensis WS11, B. tequilensis WS13, and B. tequilensis WS14. At a 20% NaCl concentration, the proteolytic activity retained was 71.4%, 65%, and 79.8% for WD01, WS11, and WS13, respectively; the activity of strain WS14 increased with 45% NaCl. Protease production by B. tequilensis WS14 with wheat, fish, and bone flours as low-cost substrates showed no differences between bone and fish flours and showed a decrease in protease production with wheat flour. The proteolytic activity in flour extracts with 20% NaCl was 82%, 75.61% and 38.04% for fish, bone and wheat flours, respectively. Data obtained in this work allow us to propose that strains isolated from environments with extreme conditions have a biotechnological potential.

Study on optimization of process parameters for enhancing the multi-hydrolytic enzyme activity in garbage enzyme produced from preconsumer organic waste

The garbage enzymes produced from preconsumer organic waste containing multi hydrolytic enzyme activity which helps to solubilize the waste activated sludge. The continuous production of garbage enzyme and its scaling up process need a globe optimized condition. In present study the effect of fruit peel composition and sonication time on enzyme activity were investigated. Garbage enzyme produced from 6g pineapple peels: 4g citrus peels pre-treated with ultrasound for 20min shows higher hydrolytic enzymes activity. Simultaneously statistical optimization tools were used to model garbage enzyme production with higher activity of amylase, lipase and protease. The maximum activity of amylase, lipase and protease were predicted to be 56.409, 44.039, 74.990U/ml respectively at optimal conditions (pH (6), temperature (37°C), agitation (218 RPM) and fermentation duration (3days)). These optimized conditions can be successfully used for large scale production of garbage enzyme with higher hydrolytic enzyme activity.

Organic solvent tolerant metallo protease of novel isolate Serratia marcescens PPB-26: production and characterization

Proteases are a class of enzymes that catalyze hydrolysis of peptide bonds of proteins. In this study, 221 proteolytic bacterial isolates were obtained by enrichment culture method from soils of various regions of Himachal Pradesh, India. From these a hyper producer of protease was screened and identified by morphological and physiological testing and by 16S rDNA sequence as Serratia marcescens PPB-26. Statistical optimization of physiochemical parameters enhanced the protease production by 75 %. Protease of S. marcescens PPB-26 was classified as a metalloprotease. It showed optimal activity at 30 °C, pH 7.5 (0.15 M Tris-HCl buffer) and with 0.8 % substrate concentration. It had K m = 0.3 %, V max = 34.5 μmol min-1 mg-1 protein and a half life of 2 days at 30 °C. The enzyme was stable in most metal ions but showed increased activity with Fe2+ and Cu2+ while strong inhibition with Co2+ and Zn2+. Further investigation showed that the enzyme could not only retain its activity in various organic solvents but also showed increased activity with methanol and ethanol. The reported metalloprotease is thus a potential candidate for carrying out industrial peptide synthesis.

Streptomyces lavendulaeProtease Inhibitor: Purification, Gene Overexpression, and 3-Dimensional Structure

Protease inhibitorstrypsin (STI1, Streptomyces trypsin inhibitor 1) has been identified, purified by ammonium sulfate precipitation and Sephadex G-100 gel filtration. SDS-PAGE of protease inhibitor showed molecular weight of approximately 10 KDa. PCR product (~1615 bp) ofsti1gene was cloned in expression vectorpACYC177/ET3dand transformed inEscherichia coliJM109.Protease inhibitorstrypsin was purified and used as antivirus against Coxsackievirus B3 (CVB3). CVB3 is one of the major causative agents of chronic, subacute, acute, and fulminant myocarditis as well as pancreatitis and aseptic meningitis. It has been reported that more than 50% of human myocarditis is associated with CVB3 infection.

Industrial applications of alkaliphiles and their enzymes--past, present and future

Alkaliphiles are microorganisms that can grow in alkaline environments, i.e. pH >9.0. Their enzymes, especially extracellular enzymes, are able to function in their catalytic activities under high alkaline pH values because of their stability under these conditions. Proteases, protein degrading enzymes, are one of the most produced enzymes in industry. Among proteases, alkaline proteases, which are added to some detergents, are the most produced. Other alkaline enzymes, e.g. alkaline cellulases, alkaline amylases, and alkaline lipases, are also adjuncts to detergents for improving cleaning efficiency. Alkaline enzymes often show activities in a broad pH range, thermostability, and tolerance to oxidants compared to neutral enzymes. Alkaliphilic Bacillus species are the most characterized organisms among alkaliphiles. They produce so many extracellular alkaline-adapted enzymes that they are often good sources for industrial enzymes. As a patent strain, the whole genome sequence of alkaliphilic Bacillus halodurans C-125 has been sequenced for the first time. In addition, an increasing number of whole genomic sequences and structural analyses of proteins in alkaliphiles, development of genetic engineering techniques and physiological analyses will reveal the alkaline adaptation mechanisms of alkaliphilic Bacillus species and the structural basis of their enzymatic functions. This information opens up the possibility of new applications. In this paper we describe, first, the physiologies of environmental adaptations, and then the applications of enzymes and microorganisms themselves in alkaliphilic Bacillus species.

Characterization of a thermostable alkaline protease produced by marine Streptomyces fungicidicus MML1614

Totally 191 different marine actinomycetes were isolated from 256 different marine samples collected from the Bay of Bengal and its associated Pulicat lake and Pichavaram mangrove, India. Among them, 157 produced caseinase, 113 produced gelatinase and 108 produced both the protease enzymes. An isolate coded as MML1614 was selected for further study as it exhibited high proteolytic activity. The MML1614 was identified as Streptomyces fungicidicus based on polyphasic taxonomical approach including 16S rRNA sequence analysis. The culture conditions were standardized for the growth and protease production in S. fungicidicus MML1614. The protease was isolated from a 6-day-old culture filtrate of S. fungicidicus MML1614 and partially purified up to 4.5-fold. The protease was optimally active at pH 9 and 40 degrees C and it was stable up to pH 11 and 60 degrees C. PMSF and NaCl inhibited the enzyme activity up to 22 and 11%, respectively. The partially purified protease removed the blood stain more effectively when combined with different detergents than the detergents alone.

Detergent alkaline proteases: enzymatic properties, genes, and crystal structures

Subtilisin-like serine proteases from bacilli have been used in various industrial fields worldwide, particularly in the production of laundry and automatic dishwashing detergents. They belong to family A of the subtilase superfamily, which is composed of three clans, namely, true subtilisins, high-alkaline proteases, and intracellular proteases. We succeeded in the large-scale production of a high-alkaline protease (M-protease) from alkaliphilic Bacillus clausii KSM-K16, and the enzyme has been introduced into compact heavy-duty laundry detergents. We have also succeeded in the industrial-scale production of a new alkaline protease, KP-43, which was originally resistant to chemical oxidants and to surfactants, produced by alkaliphilic Bacillus sp. strain KSM-KP43 and have incorporated it into laundry detergents. KP-43 and related proteases form a new clan, oxidatively stable proteases, in subtilase family A. In this review, we describe the enzymatic properties, gene sequences, and crystal structures of M-protease, KP-43, and related enzymes.

Alkaliphilic Bacillus sp. strain KSM-LD1 contains a record number of subtilisin-like serine proteases genes

The presence of 11 genes encoding subtilisin-like serine proteases was demonstrated by cloning from the genome of alkaliphilic Bacillus sp. strain KSM-LD1. This strain exoproduces the oxidatively stable alkaline protease LD-1 (Saeki et al. Curr Microbiol, 47:337-340, 2003). Among the 11 genes, six genes encoding alkaline proteases (SA, SB, SC, SD, SE, and LD-1) were expressed in Bacillus hosts. However, the other five genes for subtilisin-like proteases (SF, SG, SH, SI, and SJ) were expressed in neither Bacillus hosts nor Escherichia coli. The deduced amino acid sequences of SA, SB, SC, SF, SG, SH, SI, and SJ showed similarity to those of other subtilisin-like proteases from Bacillus strains with only 38 to 86% identity. The deduced amino acid sequence of SD was completely identical to that of an oxidatively stable alkaline protease from Bacillus sp. strain SD521, and that of SE was almost identical to that of a high-molecular mass subtilisin from Bacillus sp. strain D-6 with 99.7% identity. There are four to nine subtilisin-like serine protease genes in the reported genomes of Bacillus strains. At least 11 genes for the enzymes present in the genome of Bacillus sp. strain KSM-LD1, and this is the greatest number identified to date.

Isolation, characterization and optimization of culture parameters for production of an alkaline protease isolated from Aspergillus tamarii

Aspergillus tamarii expresses an extracellular alkaline protease that we show to be effective in removing hair from cattle hide. Large quantities of the enzyme will be required for the optimization of the enzymatic dehairing process so the growth conditions for maximum protease expression by A. tamarii were optimized for both solid-state culture on wheat bran and for broth culture. Optimal protease expression occurred, for both cultural media, at initial pH 9; the culture was incubated at 30 degrees C for 96 h using a 5% inoculum. The crude enzyme was isolated, purified and characterized using MALDI TOF TOF. The alkaline protease was homologous to the alkaline protease expressed by Aspergillus viridinutans.

Isolation and characterization of a feather-degrading enzyme from Bacillus pseudofirmus FA30-01

We isolated the feather-degrading Bacillus pseudofirmus FA30-01 from the soil sample of poultry farm. The isolate completely degraded feather pieces after liquid culture at 30 degrees C (pH 10.5) for 3 days. Strain FA30-01 is a Gram-positive, spore-forming, rod-shaped bacterium and was identified with B. pseudofirmus based on 16S rDNA analysis. The keratinase enzyme produced by strain FA30-01 was refined using ammonium sulfate precipitation, negative-ion DEAE Toyopearl exchange chromatography, and hydroxyapatite chromatography. The refinement level was 14.5-fold. The molecular weight of this enzyme was 27.5 kDa and it had an isoelectric point of 5.9. The enzyme exhibited activity at pH 5.1-11.5 and 30-80 degrees C with azokeratin as a substrate, although the optimum pH and temperature for keratinase activity were pH 8.8-10.3 and 60 degrees C, respectively. This enzyme is one of the serine-type proteases. Subtilisin ALP I and this enzyme had 90% homology in the N-terminal amino acid sequence. Since this enzyme differed from ALP I in molecular weight, heat resistance and isoelectric point, they are suggested to be different enzymes.

Production of alkaline protease with immobilized cells of Bacillus subtilis PE-11 in various matrices by entrapment technique

The purpose of this investigation was to study the effect of Bacillus subtilis PE-11 cells immobilized in various matrices, such as calcium alginate, k-Carrageenan, ployacrylamide, agar-agar, and gelatin, for the production of alkaline protease. Calcium alginate was found to be an effective and suitable matrix for higher alkaline protease productivity compared to the other matrices studied. All the matrices were selected for repeated batch fermentation. The average specific volumetric productivity with calcium alginate was 15.11 U/mL/hour, which was 79.03% higher production over the conventional free-cell fermentation. Similarly, the specific volumetric productivity by repeated batch fermentation was 13.68 U/mL/hour with k-Carrageenan, 12.44 U/mL/hour with agar-agar, 11.71 U/mL/hour with polyacrylamide, and 10.32 U/mL/hour with gelatin. In the repeated batch fermentations of the shake flasks, an optimum level of enzyme was maintained for 9 days using calcium alginate immobilized cells. From the results, it is concluded that the immobilized cells of B subtilis PE-11 in calcium alginate are more efficient for the production of alkaline protease with repeated batch fermentation. The alginate immobilized cells of B subtilis PE-11 can be proposed as an effective biocatalyst for repeated usage for maximum production of alkaline protease.

Hydrolysis of polyesters by serine proteases

The substrate specificity of alpha-chymotrypsin and other serine proteases, trypsin, elastase, proteinase K and subtilisin, towards hydrolysis of various polyesters was examined using poly(L-lactide) (PLA), poly(beta-hydroxybutyrate) (PHB), poly(ethylene succinate) (PES), poly(ethylene adipate) (PEA), poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate) (PBS/A), poly[oligo(tetramethylene succinate)-co-(tetramethylane carbonate)] (PBS/C), and poly(epsilon-caprolactone) (PCL). alpha-Chymotrypsin could degrade PLA and PEA with a lower activity on PBS/A. Proteinase K and subtilisin degraded almost all substrates other than PHB. Trypsin and elastase had similar substrate specificities to alpha-chymotrypsin.

Developments in the use of Bacillus species for industrial production

Bacillus species continue to be dominant bacterial workhorses in microbial fermentations. Bacillus subtilis (natto) is the key microbial participant in the ongoing production of the soya-based traditional natto fermentation, and some Bacillus species are on the Food and Drug Administration's GRAS (generally regarded as safe) list. The capacity of selected Bacillus strains to produce and secrete large quantities (20-25 g/L) of extracellular enzymes has placed them among the most important industrial enzyme producers. The ability of different species to ferment in the acid, neutral, and alkaline pH ranges, combined with the presence of thermophiles in the genus, has lead to the development of a variety of new commercial enzyme products with the desired temperature, pH activity, and stability properties to address a variety of specific applications. Classical mutation and (or) selection techniques, together with advanced cloning and protein engineering strategies, have been exploited to develop these products. Efforts to produce and secrete high yields of foreign recombinant proteins in Bacillus hosts initially appeared to be hampered by the degradation of the products by the host proteases. Recent studies have revealed that the slow folding of heterologous proteins at the membrane-cell wall interface of Gram-positive bacteria renders them vulnerable to attack by wall-associated proteases. In addition, the presence of thiol-disulphide oxidoreductases in B. subtilis may be beneficial in the secretion of disulphide-bond-containing proteins. Such developments from our understanding of the complex protein translocation machinery of Gram-positive bacteria should allow the resolution of current secretion challenges and make Bacillus species preeminent hosts for heterologous protein production. Bacillus strains have also been developed and engineered as industrial producers of nucleotides, the vitamin riboflavin, the flavor agent ribose, and the supplement poly-gamma-glutamic acid. With the recent characterization of the genome of B. subtilis 168 and of some related strains, Bacillus species are poised to become the preferred hosts for the production of many new and improved products as we move through the genomic and proteomic era.

Microbial alkaline proteases: from a bioindustrial viewpoint

Alkaline proteases are of considerable interest in view of their activity and stability at alkaline pH. This review describes the proteases that can resist extreme alkaline environments produced by a wide range of alkalophilic microorganisms. Different isolation methods are discussed which enable the screening and selection of promising organisms for industrial production. Further, strain improvement using mutagenesis and/or recombinant DNA technology can be applied to augment the efficiency of the producer strain to a commercial status. The various nutritional and environmental parameters affecting the production of alkaline proteases are delineated. The purification and properties of these proteases is discussed, and the use of alkaline proteases in diverse industrial applications is highlighted.

Purification and partial characterization of thermostable serine alkaline protease from a newly isolated Bacillus subtilis PE-11

The purpose of the research was to study the purification and partial characterization of thermostable serine alkaline protease from a newly isolated Bacillus subtilis PE-11. The enzyme was purified in a 2-step procedure involving ammonium sulfate precipitation and Sephadex G-200 gel permeation chromatography. The enzyme was shown to have a relative low molecular weight of 15 kd by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and was purified 21-fold with a yield of 7.5%. It was most active at 60 degrees C, pH 10, with casein as substrate. It was stable between pH 8 and 10. This enzyme was almost 100% stable at 60 degrees C even after 350 minutes of incubation. It was strongly activated by metal ions such as Ca+2, Mg+2, and Mn+2. Enzyme activity was inhibited strongly by phenylmethyl sulphonyl fluoride (PMSF) and diisopropyl fluorophosphates (DFP) but was not inhibited by ethylene diamine tetra acetic acid (EDTA), while a slight inhibition was observed with iodoacetate, p-chloromercuric benzoate (pCMB), and beta-mercaptoethanol (beta-ME). The compatibility of the enzyme was studied with commercial and local detergents in the presence of 10mM CaCl2 and 1M glycine. The addition of 10mM CaCl2 and 1M glycine, individually and in combination, was found to be very effective in improving the enzyme stability where it retained 52% activity even after 3 hours. This enzyme improved the cleansing power of various detergents. It removed blood stains completely when used with detergents in the presence of 10mM CaCl2 and 1M glycine.

The molecular surface of proteolytic enzymes has an important role in stability of the enzymatic activity in extraordinary environments

It is scientifically and industrially important to clarify the stabilizing mechanism of proteases in extraordinary environments. We used subtilisins ALP I and Sendai as models to study the mechanism. Subtilisin ALP I is extremely sensitive to highly alkaline conditions, even though the enzyme is produced by alkalophilic Bacillus, whereas subtilisin Sendai from alkalophilic Bacillus is stable under conditions of high alkalinity. We constructed mutant subtilisin ALP I enzymes by mutating the amino acid residues specific for subtilisin ALP I to the residues at the corresponding positions of amino acid sequence alignment of alkaline subtilisin Sendai. We observed that the two mutations in the C-terminal region were most effective for improving stability against surfactants and heat as well as high alkalinity. We predicted that the mutated residues are located on the surface of the enzyme structures and, on thebasis of three-dimensional modelling, that they are involved in stabilizing the conformation of the C-terminal region. As proteolytic enzymes frequently become inactive due to autocatalysis, stability of these enzymes in an extraordinary environment would depend on the conformational stability of the molecular surface concealing scissile peptide bonds. It appeared that the stabilization of the molecular surface structure was effective to improve the stability of the proteolytic enzymes.

Alkaliphiles: some applications of their products for biotechnology

The term "alkaliphile" is used for microorganisms that grow optimally or very well at pH values above 9 but cannot grow or grow only slowly at the near-neutral pH value of 6.5. Alkaliphiles include prokaryotes, eukaryotes, and archaea. Many different taxa are represented among the alkaliphiles, and some of these have been proposed as new taxa. Alkaliphiles can be isolated from normal environments such as garden soil, although viable counts of alkaliphiles are higher in samples from alkaline environments. The cell surface may play a key role in keeping the intracellular pH value in the range between 7 and 8.5, allowing alkaliphiles to thrive in alkaline environments, although adaptation mechanisms have not yet been clarified. Alkaliphiles have made a great impact in industrial applications. Biological detergents contain alkaline enzymes, such as alkaline cellulases and/or alkaline proteases, that have been produced from alkaliphiles. The current proportion of total world enzyme production destined for the laundry detergent market exceeds 60%. Another important application is the industrial production of cyclodextrin by alkaline cyclomaltodextrin glucanotransferase. This enzyme has reduced the production cost and paved the way for cyclodextrin use in large quantities in foodstuffs, chemicals, and pharmaceuticals. It has also been reported that alkali-treated wood pulp could be biologically bleached by xylanases produced by alkaliphiles. Other applications of various aspects of alkaliphiles are also discussed.