Optimization of protease activity of alkaliphilic bacteria isolated from an alkaline lake in India

Alleviation of cold stress in wheat with psychrotrophic phosphorus solubilizing Acinetobacter rhizosphaerae EU-KL44

Low-temperature stress can seriously impair plant physiology. Chilling injury leads to a complex array of cellular dysfunctions, and symptoms include chlorosis, sterility, loss of vigor, wilting, and even death of the plants. Furthermore, phosphorus limitations additionally halt the growth of plants. Low-temperature adaptive plant growth-promoting microbes through various direct and indirect mechanisms help in the survival of plants under stress conditions. The present investigation deals with isolation of P-solubilizing psychrotrophic bacteria from diverse cultivars of wheat grown in the Keylong region of Himachal Pradesh. A total of 33 P-solubilizing bacterial isolates were obtained. P-solubilizers were screened for different plant growth-promoting (PGP) attributes of K and Zn solubilization, production of IAA, siderophores, and different hydrolytic enzymes. Among 33 P-solubilizers, 8 efficient strains exhibiting multiple PGP attributes were used as bioinoculants for wheat under low-temperature stress in different in vitro and in vivo experiments. The psychrotrophic bacterial isolates positively influenced the growth and physiological parameters as well as nutrient uptake and yield of wheat and efficiently alleviated low-temperature stress. The potential of low-temperature stress adaptive and PGP microbes can be utilized in agricultural sector for amelioration of low-temperature stress and plant growth promotion. The present study deals with the isolation of psychrotrophic P-solubilizers with multiple PGP attributes and their role in alleviation of cold stress in wheat.

Enhanced fusidic acid transdermal delivery achieved by newly isolated and optimized Bacillus cereus Keratinase

The expanding interest in bioremediation of poorly degradable wastes has led to the discovery of many microbial enzymes capable of degrading recalcitrant substances such as keratinaceous wastes that are produced in vast quantities on daily basis. Such enzymes don't only work as a bioremediation tool but also have multiple beneficial applications. Hence, environmental samples were collected from sewage water, soils, animal bodies and feces in order to isolate keratinase producing organisms. Keratinolytic isolates were isolated from sewage water; soils; animal bodies; animal feces, and identified both traditionally and molecularly through 16S-rRNA sequencing to be Bacillus cereus strain. Produced keratinase was purified by centrifugation, ammonium sulfate precipitation, and HPLC, then assayed using Azokeratine based analysis. keratinase quantification yielded a 420 ± 1.63 U/mL. Optimum production was obtained at 40 °C, pH 7, 3 days incubation, 0.5 % substrate, 0.4 g/l magnesium ion, 2% v/v inoculum, 0.5 g/l NaCl, 0.4 g/l K₂HPO₄, and 0.3 g/l KH₂PO₄. Production was increased by 1.9 fold after acclimatization to reach 809 ± 2.49 U/mL in only 2 days. Thermal and pH stability testing revealed the effectiveness of the isolated keratinase over a wide range of temperatures at neutral pH. Finally, isolated keratinase enhanced fusidic acid topical penetration to treat induced deep skin bacterial infection in mice. A 1.4 fold decrease in treatment period and a 2 log cycle reduction in the viable count of Staphylococcus aureus were noticed in keratinase/fusidic acid treated mice compared to mice treated with fusidic acid alone. This study shed some light on a simple keratinase production optimization technique and suggested a promising medical application of this enzyme as a drug delivery agent.

Optimized production of extracellular alkaline protease from Aspergillus tamarii with natural by-products in a batch stirred tank bioreactor

Proteolytic enzymes are one of the significant commercially manufactured enzymes. The manufacture of extracellular alkaline protease by Aspergillus tamarii MTCC5152 was explored using several agricultural by-products as substrates viz., cottonseed meal, wheat bran, skimmed milk and soya flour in submerged fermentation, were found to be efficient for enzyme production and commercially significant. Response surface methodology (RSM) is a statistics-based experimental design, sourced to explore the impact of physical parameters on the manufacture of protease from A. tamarii in a batch stirred tank bioreactor (STBR). The four substantial variables (pH, temperature, inoculum size, and agitation) were carefully chosen for optimization analyses and the statistical pattern was created using a central composite design and the quadratic model has been developed. The optimum conditions for protease production (1.51 U mL^-1) where: pH 6.4, temperature 27 °C, inoculum size 2.6%, and agitation 327 rpm. The analysis revealed that the anticipated values were in accord with trial data with a correlation coefficient of 0.969.

Shotgun metagenome guided exploration of anthropogenically driven resistomic hotspots within Lonar soda lake of India

Anthropogenic activities mediated antibiotic resistance genes (ARGs) in the pristine aquatic bodies (lakes) is raising concern worldwide. Long read shotgun sequencing was used to assess taxonomic diversity, distribution of ARGs and metal resistance genes (MRGs) and mobile genetic elements (MGEs) in six sites within hypersaline Lonar soda lake (India) prone to various anthropogenic activities. Proteobacteria and Euryarchaeota were dominant phyla under domain Bacteria and Archaea respectively. Higher abundance of Bacteroidetes was pragmatic at sites 18LN5 and 18LN6. Functional analysis indicated 26 broad-spectrum ARGs types, not reported earlier in this ecosystem. Abundant ARG types identified were multidrug efflux, glycopepetide, bacitracin, tetracycline and aminogylcoside resistance. Sites 18LN1 and 18LN5 depicted 167 and 160 different ARGs subtypes respectively and rpoB2, bcrA, tetA(48), mupA, ompR, patA, vanR and multidrug ABC transporter genes were present in all samples. The rpoB2 gene was dominant in 18LN1, whereas bcrA gene in 18LN2-18LN6 sites. Around 24 MRGs types were detected with higher abundance of arsenic in 18LN1 and copper in 18LN2-18LN6, signifying metal contamination linked to MRGs. The bacterial taxa Pseudomonas, Thioalkalivibrio, Burkholderia, Clostridium, Paenibacillus, Bacillus and Streptomyces were significantly associated with ARGs. This study highlights the resistomic hotspots in the lake for deploying policies for conservation efforts.

Alkaline and Halophilic Protease Production by Bacillus luteus H11 and Its Potential Industrial Applications

This paper presents the results of the study on the production of protease by Bacillus luteus H11 isolated from an alkaline soda lime. B. luteus H11 was identified as an alkalohalophilic bacterium, and its extracellular serine endoprotease also showed an extreme alkali- and halotolerance. It was remarkably stable in the presence of NaCl up to 5 M. The enzyme was active in a broad range of pH values and temperatures, with an optimum pH of 10.5 and a temperature of 45 °C. It had a molecular mass of about 37 kDa and showed activity against azocasein and a synthetic substrate for the subtilisin-like protease, N-succinyl-l-phenylalanine-p-nitroanilide. The halo-alkaline protease produced by B. luteus H11 seems to be significant from an industrial perspective because of its tolerance towards high salinity and alkalinity as well as its stability against some organic solvents, surfactants and oxidants. These properties make the protease suitable for applications in food, detergent and pharmaceutical industries, and also in environmental bioremediation.

Production and Characterization of an Extracellular Acid Protease from Thermophilic Brevibacillus sp. OA30 Isolated from an Algerian Hot Spring

Proteases have numerous biotechnological applications and the bioprospection for newly-thermostable proteases from the great biodiversity of thermophilic microorganisms inhabiting hot environments, such as geothermal sources, aims to discover more effective enzymes for processes at higher temperatures. We report in this paper the production and the characterization of a purified acid protease from strain OA30, a moderate thermophilic bacterium isolated from an Algerian hot spring. Phenotypic and genotypic study of strain OA30 was followed by the production of the extracellular protease in a physiologically-optimized medium. Strain OA30 showed multiple extracellular proteolytic enzymes and protease 32-F38 was purified by chromatographic methods and its biochemical characteristics were studied. Strain OA30 was affiliated with Brevibacillus thermoruber species. Protease 32-F38 had an estimated molecular weight of 64.6 kDa and was optimally active at 50 °C. It showed a great thermostability after 240 min and its optimum pH was 6.0. Protease 32-F38 was highly stable in the presence of different detergents and solvents and was inhibited by metalloprotease inhibitors. The results of this work suggest that protease 32-F38 might have interesting biotechnological applications.

Alkaline Technosol contaminated by former mining activity and its culturable autochthonous microbiota

Technosols or technogenic substrates contaminated by potentially toxic elements as a result of iron mining causes not only contamination of the surrounding ecosystem but may also lead to changes of the extent, abundance, structure and activity of soil microbial community. Microbial biomass were significantly inhibited mainly by exceeding limits of potentially toxic metals as arsenic (in the range of 343-511 mg/kg), copper (in the range of 7980-9227 mg/kg), manganese (in the range of 2417-2670 mg/kg), alkaline and strong alkaline pH conditions and minimal contents of organic nutrients. All of the 14 bacterial isolates, belonged to 4 bacterial phyla, Actinobacteria, Firmicutes; β- and γ-Proteobacteria. Thirteen genera and 20 species of microscopic filamentous fungi were recovered. The most frequently found species belonged to genera Aspergillus (A. clavatus, A. niger, A. flavus, A. versicolor, Aspergillus sp.) with the dominating A. niger in all samples, and Penicillium (P. canescens, P. chrysogenum, P. spinulosum, Penicillium sp.). Fungal plant pathogens occurred in all surface samples. These included Bjerkandera adustata, Bionectria ochloleuca with anamorph state Clonostachys pseudochloleuca, Lewia infectoria, Phoma macrostoma and Rhizoctonia sp.

Approach toward enhancement of halophilic protease production by Halobacterium sp. strain LBU50301 using statistical design response surface methodology

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Halophilic protease producing Halobacterium sp. strain LBU50301 was isolated.

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RSM optimized the fermentation conditions to enhance halophilic protease yield.

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Optimized conditions used in bioreactor resulted about 13-fold enhancement.

A new potent halophilic protease producer, Halobacterium sp. strain LBU50301 was isolated from salt-fermented fish samples (budu) and identified by phenotypic analysis, and 16S rDNA gene sequencing. Thereafter, sequential statistical strategy was used to optimize halophilic protease production from Halobacterium sp. strain LBU50301 by shake-flask fermentation. The classical one-factor-at-a-time (OFAT) approach determined gelatin was the best nitrogen source. Based on Plackett–Burman (PB) experimental design; gelatin, MgSO₄·7H₂O, NaCl and pH significantly influenced the halophilic protease production. Central composite design (CCD) determined the optimum level of medium components. Subsequently, an 8.78-fold increase in corresponding halophilic protease yield (156.22 U/mL) was obtained, compared with that produced in the original medium (17.80 U/mL). Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values. An overall 13-fold increase in halophilic protease yield was achieved using a 3 L laboratory fermenter and optimized medium (231.33 U/mL).

Production, Purification, and Biochemical Characterization of Thermostable Metallo-Protease from Novel Bacillus alkalitelluris TWI3 Isolated from Tannery Waste

Protease enzymes in tannery industries have enormous applications. Seeking a potential candidate for efficient protease production has emerged in recent years. In our study, we sought to isolate proteolytic bacteria from tannery waste dumping site in Tamilnadu, India. Novel proteolytic Bacillus alkalitelluris TWI3 was isolated and tested for protease production. Maximum protease production was achieved using lactose and skim milk as a carbon and nitrogen source, respectively, and optimum growth temperature was found to be 40 °C at pH 8. Protease enzyme was purified using ammonium sulfate precipitation method and anion exchange chromatography. Diethylaminoethanol (DEAE) column chromatography and Sephadex G-100 chromatography yielded an overall 4.92-fold and 7.19-fold purification, respectively. The 42.6-kDa TWI3 protease was characterized as alkaline metallo-protease and stable up to 60 °C and pH 10. Ca(2+), Mn(2+), and Mg(2+) ions activated the protease, while Hg(2+), Cu(2+), Zn(2+), and Fe(2+) greatly inhibited it. Ethylenediaminetetraacetic acid (EDTA) inhibited TWI3 protease and was activated by Ca(2+), which confirmed that TWI3 protease is a metallo-protease. Moreover, this protease is capable of dehairing goat skin and also removed several cloth stains, which makes it more suitable for various biotechnological applications.

Exhaustive study of the novel hyper alkalophil, thermostable, and chelator resistant metalloprotease

Our newly discovered metalloprotease, designated as ALP NS12 was selected using gelatin agar plates with incubation at 100 °C. Subcloning of the fragments in to pUC118 to make E. coli HB101 (pPEMP01NS) with following two-step chromatography using diethylaminoethyl sepharose (DEAE-sepharose) and Sephadex G-100 columns to purify 97-kDa expressed enzyme was performed. Although activity of immobilized ALP NS12 on glass surface was established at temperatures between 70 and 120 °C and pH ranges 4.0-13.0, the optimum temperature and pH were achieved at 100 °C and 11.0, respectively. Enhancement of enzyme activity was obtained in the presence of 5 mM MnCl2 (91 %), CaCl2 (357 %), FeCl2 (175 %), MgCl2 (94 %), ZnCl2 (412 %), NiCl (86 %), NaCl (239 %), and Na-sulfate (81 %) while inhibition was observed with EDTA (5 mM), PMSF (3 mM), urea (8 M), and SDS (1 %) at 65, 37, 33, and 42 %, respectively. Consequently, the enzyme was well analyzed using crystallography and protein modeling. ALP NS12 can be applied in industrial processes at extreme temperatures and under highly basic conditions, chelators, and detergents.

Application of statistical experimental design for optimisation of bioinsecticides production by sporeless Bacillus thuringiensis strain on cheap medium

In order to overproduce bioinsecticides production by a sporeless Bacillus thuringiensis strain, an optimal composition of a cheap medium was defined using a response surface methodology. In a first step, a Plackett-Burman design used to evaluate the effects of eight medium components on delta-endotoxin production showed that starch, soya bean and sodium chloride exhibited significant effects on bioinsecticides production. In a second step, these parameters were selected for further optimisation by central composite design. The obtained results revealed that the optimum culture medium for delta-endotoxin production consists of 30 g L⁻¹ starch, 30 g L⁻¹ soya bean and 9 g L⁻¹ sodium chloride. When compared to the basal production medium, an improvement in delta-endotoxin production up to 50% was noted. Moreover, relative toxin yield of sporeless Bacillus thuringiensis S22 was improved markedly by using optimised cheap medium (148.5 mg delta-endotoxins per g starch) when compared to the yield obtained in the basal medium (94.46 mg delta-endotoxins per g starch). Therefore, the use of optimised culture cheap medium appeared to be a good alternative for a low cost production of sporeless Bacillus thuringiensis bioinsecticides at industrial scale which is of great importance in practical point of view.

Characterization of detergent compatible protease of a halophilic Bacillus sp. EMB9: differential role of metal ions in stability and activity

A moderately halophilic protease producer, Bacillus sp. strain isolated from sea water is described. The protease is purified to homogeneity by ammonium sulphate precipitation and CM cellulose chromatography. The serine protease has a molecular mass of 29 kDa. Enzymatic characterization of protease revealed K(m) 2.22 mg mL(-1), Vmax 1111.11 U mL(-1), pH optimum 9.0, t1/2 190 min at 60°C and salt optima 1% (w/v) NaCl. The protease is remarkably stable in hydrophilic and hydrophobic solvents at high concentrations. The purified preparation is unstable at room temperature. Ca(2+) ions are required for preventing this loss of activity. Interestingly, the activity and stability are modulated differentially. Whereas, divalent cation Ca(2+) are involved in maintaining stability in solution at room temperature by preventing unfolding, monovalent Na(+) and K(+) ions participate in regulating the activity and assist in refolding of the enzyme. Application of the protease is shown in efficient removal of blood stain.

Cold-active hydrolases producing bacteria from two different sub-glacial Himalayan lakes

Microorganisms, native to the cold environments have successfully acclimatized their physiological, metabolic, and biological features, exhibiting uniqueness in their enzymes, proteins, and membrane structures. These cold-active enzymes have immense biotechnological potential. The diversity of culturable bacteria in two different water lakes (the sub-glacial freshwater and the brackish) of Himalayas was analyzed using SYBR green staining and cultural methods. A total of 140 bacteria were isolated and were grouped as psychrophiles, psychrotrophs, and psychrotolerant organisms, based on their optimal temperature for growth. The amplified ribosomal DNA restriction analysis using three restriction enzymes facilitated the grouping of these isolates into 96 genotypes at ≥85% polymorphism. Phylogenetic analysis using 16S rRNA gene sequences revealed that the bacterial strains from both lakes belonged to Firmicutes, Proteobacteria (α, β, and γ) or Actinobacteria. Screening of the germplasm for the activity of different cold-active hydrolases such as protease, amylase, xylanase, and cellulase, revealed that about 16 isolates were positive, and exhibiting a wide range of stability at various temperature and pH. Our results suggest that the distinctly different ecosystems of sub-glacial freshwater and brackish water lakes have diverse groups of bacteria, which can be an excellent source of extracellular hydrolases with a wide range of thermal stability.

Phylogenetic analysis of alkaline proteinase producing fluorescent pseudomonads associated with green gram (Vigna radiata L.) rhizosphere

Fifty fluorescent pseudomonads were isolated from rhizospheric soil of green gram from nearby area of Kaziranga, Assam, India and assayed for their extracellular proteinase production. Out of these isolates, 20 were found to be prominent in proteinase production. Genetic diversity of the 20 isolates were analyzed through BOX-PCR fingerprinting and 16S rDNA-RFLP along with three reference strains, viz., Pseudomonas fluorescens (NCIM2099(T)), Pseudomonas aureofaciens (NCIM2026(T)), and Pseudomonas aeruginosa (MTCC2582(T)). BOX-PCR produced two distinct clusters at 56% similarity coefficient and seven distinct BOX profiles. 16S rDNA-RFLP with three tetra-cutters restriction enzymes (HaeIII, AluI, and MspI) revealed two major clusters A and B; cluster A contained only single isolate FPS9 while the rest of 22 isolates belonged to the cluster B. Based on phenotypic characters and 16S rDNA sequence similarity, all the eight highly proteinase-producing strains were affiliated with P. aeruginosa. The proteinase was extracted from two most prominent strains (KFP1 and KFP2), purified by a three-step process involving (NH(4))(2)SO(4) precipitation, gel filtration, and ion exchange chromatography. The enzyme had an optimal pH of 8.0 and exhibit highest activity at 60°C and 37°C by KFP1 and KFP2 respectively. The specific activities were recorded as 75,050 (for KFP1) and 81,320 U/mg (for KFP2). The purified enzyme was migrated as a single band on native and SDS-PAGE with a molecular mass of 32 kDa. Zn(2+), Cu(2+), and Ni(2+) ion inhibited the enzyme activity. Enzyme activity was also inhibited by EDTA established as their metallo-proteinase nature.

Comparative one-factor-at-a-time, response surface (statistical) and bench-scale bioreactor level optimization of thermoalkaline protease production from a psychrotrophic Pseudomonas putida SKG-1 isolate

BACKGROUND

Production of alkaline protease from various bacterial strains using statistical methods is customary now-a-days. The present work is first attempt for the production optimization of a solvent stable thermoalkaline protease by a psychrotrophic Pseudomonas putida isolate using conventional, response surface methods, and fermentor level optimization.

RESULTS

The pre-screening medium amended with optimized (w/v) 1.0% glucose, 2.0% gelatin and 0.5% yeast extract, produced 278 U protease ml(-1) at 72 h incubation. Enzyme production increased to 431 Uml(-1) when Mg2+ (0.01%, w/v) was supplemented. Optimization of physical factors further enhanced protease to 514 Uml(-1) at pH 9.0, 25°C and 200 rpm within 60 h. The combined effect of conventionally optimized variables (glucose, yeast extract, MgSO4 and pH), thereafter predicted by response surface methodology yielded 617 U protease ml(-1) at glucose 1.25% (w/v), yeast extract 0.5% (w/v), MgSO4 0.01% (w/v) and pH 8.8. Bench-scale bioreactor level optimization resulted in enhanced production of 882 U protease ml(-1) at 0.8 vvm aeration and 150 rpm agitation during only 48 h incubation.

CONCLUSIONS

The optimization of fermentation variables using conventional, statistical approaches and aeration/agitation at fermentor level resulted in ~13.5 folds increase (882 Uml(-1)) in protease production compared to un-optimized conditions (65 Uml(-1)). This is the highest level of thermoalkaline protease reported so far by any psychrotrophic bacterium.

Enzymatic depilation of animal hide: identification of elastase (LasB) from Pseudomonas aeruginosa MCM B-327 as a depilating protease

Conventional leather processing involving depilation of animal hide by lime and sulphide treatment generates considerable amounts of chemical waste causing severe environmental pollution. Enzymatic depilation is an environmentally friendly process and has been considered to be a viable alternative to the chemical depilation process. We isolated an extracellular protease from Pseudomonas aeruginosa strain MCM B-327 with high depilation activity using buffalo hide as a substrate. This 33 kDa protease generated a peptide mass fingerprint and de novo sequence that matched perfectly with LasB (elastase), of Pseudomonas aeruginosa. In support of this data a lasB mutant of MCM B-327 strain lacked depilatory activity and failed to produce LasB. LasB heterologously over-produced and purified from Escherichia coli also exhibited high depilating activity. Moreover, reintroduction of the lasB gene to the P. aeruginosa lasB mutant via a knock-in strategy also successfully restored depilation activity thus confirming the role of LasB as the depilating enzyme.

Comparison of protease activities in different Bacillus licheniformis strains using wastewater sludge and synthetic soy medium as raw material

The production of extracellular protease by different Bacillus licheniformis strains (ATCC 21415, ATCC 21417 and ATCC 21424) was tested in wastewater sludge as a raw material as well as in synthetic soy medium to compare the capacity of protease production by different strains and to compare the capacity of the medium to provide nutrients for enzyme synthesis. All of the strains showed similar activities in both media. The protease activity was very high in the fermentor in both of the media compared with the shake flask. Results from microbial selection indicated that ATCC 21424 had high potential for protease production using sludge as a growth medium. The observation from this study suggested that wastewater sludge could be used as a raw material (nutrient source) to produce protease for industrial applications.

Keratinolytic activity of Bacillus megaterium F7-1, a feather-degrading mesophilic bacterium

The aim of this study was to investigate environmental conditions affecting chicken feather degradation and keratinolytic enzyme production by Bacillus megaterium F7-1, a feather-degrading mesophilic bacterium. B. megaterium F7-1 degraded whole chicken feather completely within 7 days. The bacterium grew with an optimum at pH 7.0-11.0 and 25-40 degrees C, where maximum keratinolytic activity was also observed. The production of keratinolytic enzyme by B. megaterium F7-1 was inducible with feather. Keratinolytic enzyme production by B. megaterium F7-1 at 0.6% (w/v) skim milk was 468U/ml, which was about 9.4-fold higher than that without skim milk. The amount of keratinolytic enzyme production depended on feather concentrations. The degradation rate of autoclaved chicken feathers by cell-free culture supernatant was 26% after 24h of incubation, but the degradation of untreated chicken feathers was unsuccessful. B. megaterium F7-1 effectively degraded feather meal, duck feather and human nail, whereas human hair and sheep wool showed relatively low degradation rates. B. megaterium F7-1 presented high keratinolytic activity and was very effective in feather degradation, providing potential use for biotechnological processes of keratin hydrolysis.

Moderately halophilic, alkalitolerantHalomonas campisalis MCM B-365 from Lonar Lake, India

Seven bacterial isolates obtained from sediment and water samples, collected from the alkaline Lonar Lake were identified on the basis of their morphological, physiological and biochemical characteristics and were confirmed by 16S rDNA sequencing to be Halomonas campisalis. They were capable of using a variety of electron donors and were found to grow in the presence of sodium chloride (NaCl) up to 4 M, at pH from 7 to 11, 9 being the optimum. The isolates could grow over a wide range of temperatures (from 4 to 45 degrees C) and showed temperature-dependent salt tolerance. They exhibited requirement of sodium for growth and could grow in any medium where NaCl is replaced by NaNO(3) and Na(2)S(2)O(3) but not in the presence of salts like LiCl, MgCl(2) . 6H(2)O, KCl and NH(4)Cl. One of the seven isolates, ARI 351, was able to produce lipase at pH-9.0, while two isolates, ARI 351 and ARI 360, could accumulate polyhydroxyalkanoic acid (PHA) granules when grown in a medium containing maltose. Thus the H. campisalis isolated from Lonar Lake was different from the previously reported one, with respect to its biotechnological potential for production of Lipase and PHA.

Production and partial characterization of dehairing protease from Bacillus cereus MCM B-326

Bacillus cereus MCM B-326, isolated from buffalo hide, produced an extracellular protease. Maximum protease production occurred (126.87+/-1.32 U ml(-1)) in starch soybean meal medium of pH 9.0, at 30 degrees C, under shake culture condition, with 2.8 x 10(8) cells ml(-1) as initial inoculum density, at 36 h. Ammonium sulphate precipitate of the enzyme was stable over a temperature range of 25-65 degrees C and pH 6-12, with maximum activity at 55 degrees C and pH 9.0. The enzyme required Ca(2+) ions for its production but not for activity and/or stability. The partially purified enzyme exhibited multiple proteases of molecular weight 45 kDa and 36 kDa. The enzyme could be effectively used to remove hair from buffalo hide indicating its potential in leather processing industry.

Production of alkaline protease from an alkaliphilic actinomycete

The repression of alkaline protease synthesis from alkaliphilic actinomycete was studied by using glucose, peptone, yeast extract, KH2PO4 and amino acids; tyrosine, tryptophan, lysine, and arginine. There was a critical limit of stimulation of enzyme production by these components. Crude components such as molasses, wheat flour, and wheat bran were found to be effective for growth and enzyme production. The high level of enzyme production using agro-industrial by-products is commercially significant due to cheap nature of these sources. The findings are quite attractive, as only few actinomycetes, particularly alkaliphilic ones, have so far been explored for their enzymatic potential and regulation of enzyme synthesis.