Purification and characterization of a thermostable alkaline protease from alkalophilic Bacillus pumilus

Characterization of a thermostable protease from Bacillus subtilis BSP strain

This study used conservative one variable-at-a-time study and statistical surface response methods to increase the yields of an extracellular thermostable protease secreted by a newly identified thermophilic Bacillus subtilis BSP strain. Using conventional optimization techniques, physical parameters in submerged fermentation were adjusted at the shake flask level to reach 184 U/mL. These physicochemical parameters were further optimized by statistical surface response methodology using Box Behnken design, and the protease yield increased to 295 U/mL. The protease was purified and characterized biochemically. Both Ca2+ and Fe2+ increased the activity of the 36 kDa protease enzyme. Based on its strong inhibition by ethylenediaminetetracetate (EDTA), the enzyme was confirmed to be a metalloprotease. The protease was also resistant to various organic solvents (benzene, ethanol, methanol), surfactants (Triton X-100), sodium dodecyl sulfate (SDS), Tween 20, Tween-80 and oxidants hydrogen per oxide (H2O2). Characteristics, such as tolerance to high SDS and H2O2 concentrations, indicate that this protease has potential applications in the pharmaceutical and detergent industries.

Molecular Cloning, Characterization, and Application of Organic Solvent-Stable and Detergent-Compatible Thermostable Alkaline Protease from Geobacillus thermoglucosidasius SKF4

Several thermostable proteases have been identified, yet only a handful have undergone the processes of cloning, comprehensive characterization, and full exploitation in various industrial applications. Our primary aim in this study was to clone a thermostable alkaline protease from a thermophilic bacterium and assess its potential for use in various industries. The research involved the amplification of the SpSKF4 protease gene, a thermostable alkaline serine protease obtained from the Geobacillus thermoglucosidasius SKF4 bacterium through polymerase chain reaction (PCR). The purified recombinant SpSKF4 protease was characterized, followed by evaluation of its possible industrial applications. The analysis of the gene sequence revealed an open reading frame (ORF) consisting of 1,206 bp, coding for a protein containing 401 amino acids. The cloned gene was expressed in Escherichia coli. The molecular weight of the enzyme was measured at 28 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The partially purified enzyme has its highest activity at a pH of 10 and a temperature of 80°C. In addition, the enzyme showed a half-life of 15 h at 80°C, and there was a 60% increase in its activity at 10 mM Ca2+ concentration. The activity of the protease was completely inhibited (100%) by phenylmethylsulfonyl fluoride (PMSF); however, the addition of sodium dodecyl sulfate (SDS) resulted in a 20% increase in activity. The enzyme was also stable in various organic solvents and in certain commercial detergents. Furthermore, the enzyme exhibited strong potential for industrial use, particularly as a detergent additive and for facilitating the recovery of silver from X-ray film.

Alkaline Thermo- and Oxidant-Stable Protease from Bacillus pumilus Strain TNP93: Laundry Detergent Formulations

The study aims to produce a detergent-compatible and alkaline thermophilic protease from a Bacillus strain and to investigate its usability as a detergent bio-additive. The protease-producing bacterium was identified as Bacillus pumilus strain TNP93 according to the 16S rRNA sequence. The bacterium optimally synthesized the protease at 40 °C and pH 10 in 40 h. The raw protease displayed its optimum activity at pH 10 and 60 °C and its stability between pH 6-13 and 30-100 °C for 24 h. The molecular mass of the proteolytic band was estimated to be about 85 kDa. The protease was not inhibited by any of the metal ions used (Ba2+, Ca2+, Co2+, Cu2+, Mg2+, Mn2+, Zn2+). 97 and 90% of its original activity with 5 mM PMSF and EDTA remained. The activity was measured as 84, 124, and 95%, respectively, in the presence of 1% concentrations of Tween 20, Tween 80, and Triton X-100. In addition, all of its activity was preserved when the enzyme was exposed to 5% H2O2. The end products of casein were detected as tyrosine, aspartic acid, glycine, and cysteine by thin-layer chromatography. Considering the wash performance analysis, the mix of 1% commercial detergent and enzyme almost removed all of the protein-based stains (blood and egg yolk albumin). These remarkable findings indicate that the alkaline, thermo-, and oxidant-stable TNP93 protease is a valuable candidate for usage as a biological additive in various laundry detergents.

Heterologous Expression and Structural Elucidation of a Highly Thermostable Alkaline Serine Protease from Haloalkaliphilic Actinobacterium, Nocardiopsis sp. Mit-7

A highly thermostable alkaline serine protease gene (SPSPro, MN429015) obtained from haloalkaliphilic actinobacteria, Nocardiopsis sp. Mit-7 (NCIM-5746), was successfully cloned and overexpressed in Escherichia coli BL21 under the control of the T7 promoter in the pET Blue1 vector leading to a 20-kDa gene product. The molecular weight of the recombinant alkaline protease, as determined by SDS-PAGE and the Mass Spectrometer (MALDI-TOF), was 34 kDa. The structural and functional attributes of the recombinant thermostable alkaline serine protease were analyzed by Bioinformatic tools. 3D Monomeric Model and Molecular Docking established the role of the amino acid residues, aspartate, serine, and tryptophan, in the active site of thealkaline protease.The activity of the recombinant alkaline protease was optimal at 65 °C, 5 °C higher than its native protease. The recombinant protease was also active over a wide range of pH 7.0-13.0, with a maximal activity of 6050.47 U/mg at pH 9. Furthermore, the thermodynamic parameters of the immobilized recombinant alkaline protease suggested its reduced vulnerability against adverse conditions under which the enzyme has to undergo varied applications.

Feather protein lysate optimization and feather meal formation using YNDH protease with keratinolytic activity afterward enzyme partial purification and characterization

Incubation parameters used for the creation of a protein lysate from enzymatically degraded waste feathers using crude keratinase produced by the Laceyella sacchari strain YNDH were optimized using the Response Surface Methodology (RSM); amino acids quantification was also estimated. The optimization elevated the total protein to 2089.5 µg/ml through the application of the following optimal conditions: a time of 20.2 h, a feather concentration (conc.) of 3 g%, a keratinase activity of 24.5 U/100 ml, a pH of 10, and a cultivation temperature of 50 °C. The produced Feather Protein Lysate (FPL) was found to be enriched with essential and rare amino acids. Additionally, this YNDH enzyme group was partially purified, and some of its characteristics were studied. Crude enzymes were first concentrated with an Amicon Ultra 10-k centrifugal filter, and then concentrated proteins were applied to a "Q FF" strong anion column chromatography. The partially purified enzyme has an estimated molecular masses ranging from 6 to 10 kDa. The maximum enzyme activity was observed at 70 °C and for a pH of 10.4. Most characteristics of this protease/keratinase group were found to be nearly the same when the activity was measured with both casein and keratin-azure as substrates, suggesting that these three protein bands work together in order to degrade the keratin macromolecule. Interestingly, the keratinolytic activity of this group was not inhibited by ethylenediamine tetraacetic acid (EDTA), phenylmethanesulfonyl fluoride (PMSF), or iron-caused activation, indicating the presence of a mixed serine-metallo enzyme type.

A deep-sea hydrogen peroxide-stable alkaline serine protease from Aspergillus flavus

We report here the production of an alkaline serine protease by Aspergillus flavus isolated at 5600-m depth from deep-sea sediments of the Central Indian Basin. When grown on defatted groundnut oil meal at 30 °C for 48-72 h, this fungal isolate produced 2000-2500 ACU mL^-1 of alkaline protease. The purified protease had activity optima at pH 10.0 and 45 °C. It was a thiol-independent serine protease, identified as an alkaline serine protease ALP1 with a molecular mass of 42.57 kDa. The thermostability and activity of the enzyme increased at 60 °C, in the presence of additives such as sucrose, Tween 20, sorbitol, Ca²⁺ and glycerol and was not adversely affected by H₂O₂ indicating its potential as a detergent additive.

Enzymatic Potential of Bacteria and Fungi Isolates from the Sewage Sludge Composting Process

The aim of this study was the isolation and characterisation of the fungi and bacteria during the composting process of sewage sludge under a semipermeable membrane system at full scale, in order to find isolates with enzymatic activities of biotechnological interest. A total of 40 fungi were isolated and enzymatically analysed. Fungal culture showed a predominance of members of Ascomycota and Basidiomycota division and some representatives of Mucoromycotina subdivision. Some noticeable fungi isolated during the mesophilic and thermophilic phase were Aspergillus, Circinella, and Talaromyces. During the maturation phase, some lignin modifying enzyme producers, like Purpureocillium, Thielavia, Bjerkandera, or Dichotomyces, were found. Within this group, Thielavia and Bjerkandera showed high activity with production of laccases and peroxidases. In the bacterial culturome, a total of 128 strains were selected and enzymatically analysed. Bacillales, Actinomycetales, Pseudomonadales, and Lactobacillales were the orders most represented in culture-bacteria. Bacillus pumilus, B. stratosphericus, B. safensis, and Pseudomonas formosensis were the species most efficient in enzyme production, particularly peroxidases, polyphenol oxidases ammonifying activity, and amylases. These results showed that sewage sludge composting piles could represent a source of microorganisms which have adapted to adverse conditions.

Biochemical characterization of a partially purified protease from Aspergillus terreus 7461 and its application as an environmentally friendly dehairing agent for leather industry

Proteases can be used in several biotechnological processes including detergent, food and leather industries. In the leather industry, dehairing is carried out by chemicals, which pollute the environment. Therefore, to make the hair removal process environmentally friendly, a protease produced by Aspergillus terreus has been purified, biochemically characterized and had an efficient ability to remove hair from bovine leather. The protease was produced using 1% wheat bran and was purified 2.3-fold using two chromatographic steps showing a molecular weight of 90 kDa. Optimal temperature and pH were 50 °C and 6.5, respectively. Thermal stability was up to 1 h at 50 °C. Protease was stable to detergents like Tween 80 and to organic solvents. The activity was activated by Ca²⁺ and inhibited by Hg²⁺ and Cu²⁺. The enzyme was classified as serine protease, by the inhibition by PMSF and was stable to reducing agents. It hydrolyzed casein, azocasein, BSA, egg albumin and BTpNA. The Km and Vmax values were 0.65 ± 0.03 mg/mL and 3.66 ± 0.18 μmol/min, respectively. Remarkable properties about temperature, pH, stability to detergents and reducing agents ensure that the protease from A. terreus can be an excellent candidate for industrial applications, particularly in the leather industry.

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.

Degradation of fluorene and phenanthrene in PAHs-contaminated soil using Pseudomonas and Bacillus strains isolated from oil spill sites

Biodegradation of 3-ring and 4-ring polycyclic aromatic hydrocarbons (PAHs) model (fluorene, phenanthrene, fluoranthene and pyrene) were investigated. Twenty-seven bacterial strains were isolated from contaminated-site by oil spills. PAHs-degrading bacteria were screened to select high tolerant species for ensuring an efficient bioremediation. Each of the isolated bacterial strains was grown under different PAHs concentrations (250, 500, 1000 and 1500 mg/L). Among the 27 strains, 8 resulted to be resistant to high concentration level of PAHs (1500 mg/L) and thereof can use PAHs as sole source of carbon and energy. The most tolerant strains were molecularly identified using mass spectrometer MALDI-TOF VITEK MS and 16S rDNA sequencing approaches. The identified bacterial strains Pseudomonas stutzeri (P. stutzeri), Bacillus simplex (B. simplex) and Bacillus pumilus (B. pumilus) were used for the bioremediation experiment of soils contaminated by PAHs. The studies were conducted under controlled conditions using soil spiked with a mixture of the target PAHs and the three microcosm strains. The results revealed that only fluorene and phenanthrene, which are low molecular weight PAHs, were degraded efficiently within 72 days of test organism incubation. These degradations were about 65-86% and 86-95% for fluorene and phenanthrene, respectively. At the same time and conversely to fluorene and phenanthrene, the high molecular weight PAHs, pyrene and fluoranthene were recalcitrant to these selected microbial strains. The biodegradation kinetics of both fluorene and phenanthrene were fit a first order rate with R² values ranging from 0.88 to 0.92. The half-lives of phenanthrene (2.4-2.7 days) and those of fluorene (3.5-4.6 days) were all less than 10 days, delineating therefore acclimatization with the strains.

Purification and characterization of alkaline soda-bleach stable protease from Bacillus sp. APP-07 isolated from Laundromat soil

The detergent-compatible alkaline protease was produced from the bacterial strain Bacillus sp. APP-07 isolated from Laundromat soil of Solapur, Maharashtra, India. The culture was grown in 1000 ml capacity baffled flask with a working volume of 100 ml and incubated at 55 °C for 33 h on a rotary shaker. After incubation, alkaline protease was partially purified by the sequential method of acetone precipitation followed by nominal molecular weight limit (NMWL) cut-off ultrafiltration using 50 K and 10 K filters. Finally, Sephadex G-100 gel filtration chromatographic purification was performed to obtain 3.12 fold purified alkaline protease enzyme with a 66.67% final yield. The purified enzyme showed 31907.269 units (U) of enzyme activity containing 8741.718 U/mg of specific enzyme activity. The molecular weight of the enzyme was confirmed about 33.0 kDa (kDa) by the SDS-PAGE analysis. The purified enzyme was stable at higher pH and temperature range, with an optimum pH 10.5 and temperature 55 °C. The enzyme showed excellent stability and compatibility in various detergents, surfactants, bleach, and oxidizing agents. The enzyme activity enhanced in the presence of Ca2+, Cu2+, and surfactants, whereas; the phenylmethylsulphonyl fluoride (PMSF) and Diisopropyl fluorophosphate (DFP) completely inhibit the enzymatic activity, which pointed out that the enzyme affiliated to serine-centered metalloproteases family. In conclusion, the remarkable tolerance and stability of the enzyme explored the promising candidature for the several potential applications in the laundry detergents. The sustainability of the enzyme might serve several possible applications in the laundry detergents, leather industries, and other harsh industrial processes.

Characterization of thermostable alkaline proteases from Bacillus infantis SKS1 isolated from garden soil

Proteases are one of the largest groups of hydrolytic enzymes constituting about 60% of total worldwide sales of industrial enzymes due to their wide applications in detergent, leather, textile, food and pharmaceutical industry. Microbial proteases have been preferred over animal and plant proteases because of their fundamental features and ease in production. Bacillus infantis SKS1, an alkaline protease producing bacteria has been isolated from garden soil of north India and identified using morphological, biochemical and molecular methods. 16S rDNA sequence amplified using universal primers has 99% sequence identity with corresponding gene sequence of Bacillus infantis strain FM 34 and Bacillus sp. Beige. The bacterial culture and its 16S rDNA gene sequence have been deposited to Microbial Culture Collection (Pune, India) with accession number MCC 3035 and GenBank with accession number KR092197 respectively. The partially purified extract of Bacillus infantis SKS1 was thermostable and active in presence of Mg2+, acetyl acetone and laundry detergents implicating its application in industry. Production of these enzymes using this strain was maximized by optimization of various parameters including temperature, pH, media components and other growth conditions. Our results show that fructose and dextrose serve as the best carbon sources for production of these enzymes, highlighting the use of this strain for enzyme production utilizing relatively inexpensive substrates like beet molasses and corn steep liquor. Additionally, this strain showed maximum production of enzymes at 40°C similar to bacterial species used for commercial production of alkaline proteases. Characterization of alkaline proteases from this strain of Bacillus infantis and optimization of parameters for its production would help in understanding its industrial application and large-scale production.

Structural characterization, catalytic, kinetic and thermodynamic properties of Keratinase from Bacillus pumilus FH9

Bacillus pumilus FH9 keratinase was purified to homogeneity with a 59.9% yield through a series of three steps. The purified enzyme was a monomeric protein with a molecular mass around 50kDa and containing 7.3% carbohydrates. The pure B. pumilus FH9 keratinase was optimally active at pH 9.0 and 60°C. The calculated activation energy for keratin hydrolysis was 24.52kJmol^-1 and its temperature quotient (Q₁₀) was 1.19. The calculated values of thermodynamic parameters for keratin hydrolysis were as follows: ΔH*=21.75kJmol^-1, ΔG*=65.86kJmol^-1 ΔS*=-132.46Jmol^-1K^-1, (ΔG*_E-S)=4.74kJmol^-1 and ΔG*_E-T=-11.254kJmol^-1. The pure keratinase exhibited K_m, V_max, k_cat and k_cat/K_m of 5.55mg/ml keratin, 5882Umgprotein^-1 323.54s^-1 and 58.28 (s^-1/mgml^-1). The calculated half-life time at 50, 60, 70 and 80°C was 90.69, 59.1, 16.62 and 9.48min, respectively. Similarly, the thermodynamic parameters for irreversible thermal inactivation at temperature ranging from 50 to 80°C were determined. The pure enzyme was stimulated by Ca²⁺ and Mg²⁺. However, Zn²⁺, EDTA, Co²⁺ and Hg²⁺ significantly inhibited the enzyme activity. The purified enzyme was able to hydrolyze different substrates showing its higher proteolytic activity on casein, bovine serum albumin, and collagen, followed by feather, horn and wool.

Purification and partial characterization of serine-metallokeratinase from a newly isolated Bacillus pumilus NRC21

A serine metallokeratinase enzyme (30 kDa) produced by a newly isolated Bacillus strain (Bacillus pumilus NRC21) cultivated under optimized conditions in medium containing chicken feather meal was purified and characterized in a set of biochemical assays. The purification was carried out using two successive chromatographic steps; cation exchange chromatography on CM-cellulose and gel filtration on sephadex G-100 columns. The purified enzyme showed a specific activity of 2000 units/mg protein against 170 units/mg protein for crude extract with 12 fold purification. The enzymatic activity of the keratinase stimulated by (Na(+), K(+), Mg(2+)), Hg(+2) had no effect, and inhibited by entire tested cations, serine and metalloproteinase inhibitors, therefore it can be considered as a serine metalloenzyme. The optimum pH and temperature for the purified enzyme were (7.5, 8.5) and (50, 45 °C) when using keratin azure and azocasein as substrates, respectively. The purified enzyme was highly stable at broad pH and temperature ranged (5-10) and (20-60 °C), respectively and its thermoactivity and thermostability were enhanced in the presence of 5 mM Mg(+2). These results suggest that the purified keratinase may be used in several industrial applications.

Extracellular α-Galactosidase from Trichoderma sp. (WF-3): Optimization of Enzyme Production and Biochemical Characterization

Trichoderma spp. have been reported earlier for their excellent capacity of secreting extracellular α-galactosidase. This communication focuses on the optimization of culture conditions for optimal production of enzyme and its characterization. The evaluation of the effects of different enzyme assay parameters such as stability, pH, temperature, substrate concentrations, and incubation time on enzyme activity has been made. The most suitable buffer for enzyme assay was found to be citrate phosphate buffer (50 mM, pH 6.0) for optimal enzyme activity. This enzyme was fairly stable at higher temperature as it exhibited 72% activity at 60°C. The enzyme when incubated at room temperature up to two hours did not show any significant loss in activity. It followed Michaelis-Menten curve and showed direct relationship with varying substrate concentrations. Higher substrate concentration was not inhibitory to enzyme activity. The apparent Michaelis-Menten constant (K_m), maximum rate of reaction (V_max), K_cat, and catalytic efficiency values for this enzyme were calculated from the Lineweaver-Burk double reciprocal plot and were found to be 0.5 mM, 10 mM/s, 1.30 U mg⁻¹, and 2.33 U mg⁻¹ mM⁻¹, respectively. This information would be helpful in understanding the biophysical and biochemical characteristics of extracellular α-galactosidase from other microbial sources.

Purification and characterization of detergent stable alkaline protease from Bacillus amyloliquefaciens SP1 isolated from apple rhizosphere

A thermostable extracellular alkaline protease producing Bacillus amyloliquefaciens SP1 was isolated from apple rhizosphere having multifarious plant growth promoting activities. Strain SP1 was purified to 6.48-fold using four-step purification protocol and characterized in detail for its robustness and ecofriendly application in leather and detergent industries. Structural analysis revealed that the protease was monomeric and had a molecular weight of 43 kDa. It exhibited optimum activity at 60°C in alkaline environment (pH 8.0) and stable in the presence of surfactants and oxidizing agents. Enzyme was thermostable at 50°C and retained more than 70% activity after 30 min incubation. It has shown stain removal property and dehairing of goat skin without chemical assistance and hydrolyzing fibrous proteins. This protease showed Km of 0.125 mg ml(-1) and V(max) of 12820 μg ml(-1) indicating its excellent affinity and catalytic role. Thermal inactivation of the pure enzyme followed first-order kinetics. The half life of the pure enzyme at 50, 60, and 65°C was 77, 19.80, and 13.33 min, respectively. The activation energy was 37.19 KJ mol(-1). The results suggest that the B. amyloliquefaciens SP1 has a potential application in different industries.

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.

Production and Characterization of Alkaline Protease from a High Yielding and Moderately Halophilic Strain of SD11 Marine Bacteria

A marine bacterium SD11, which was isolated from sea muds (Geziwo Qinhuangdao Sea area, China), was used to produce thermostable alkaline serine nonmetal protease in the skim milk agar plate medium with 10% NaCl. The optimal temperature about the manufacture of the extracellular protease was ~60°C. The crude enzyme was stable at 20–50°C. The activity was retained to 60% and 45% after heating for 1 h at 60 and 70°C, respectively. The protease was highly active in a wide pH scope (8.0–10.0) and maximum protease activity exhibited at pH 10.0. The activity was restrained by phenylmethylsulfonyl fluoride (PMSF) but mildly increased (~107%) in the presence of ethylenediaminetetraacetic acid (EDTA), indicating that the production contains serine-protease(s) and nonmetal protease(s). Moreover, the crude alkaline protease was active with the 5 mM Ca2+, Mn2+, Zn2+, Cu2+, Na+, and K+that existed separately. In addition, the protease showed superduper stability when exposed to an anionic surfactant (5 mM SDS), an oxidizing agent (1% H2O2), and several organic solvents (methanol, isopropanol, and acetone). These results suggest that the marine bacterium SD11 is significant in the industry from the prospects of its ability to produce thermally stable alkaline protease.

Optimization and characterization of alkaline protease and carboxymethyl-cellulase produced by Bacillus pumillus grown on Ficus nitida wastes

The potentiality of 23 bacterial isolates to produce alkaline protease and carboxymethyl-cellulase (CMCase) on Ficus nitida wastes was investigated. Bacillus pumillus ATCC7061 was selected as the most potent bacterial strain for the production of both enzymes. It was found that the optimum production of protease and CMCase were recorded at 30 °C, 5% Ficus nitida leaves and incubation period of 72 h. The best nitrogen sources for protease and CMCase production were yeast extract and casein, respectively. Also maximum protease and CMCase production were reported at pH 9 and pH 10, respectively. The enzymes possessed a good stability over a pH range of 8–10, expressed their maximum activities at pH10 and temperature range of 30–50 °C, expressed their maximum activities at 50 °C. Ions of Hg²⁺, Fe2+ and Ag⁺ showed a stimulatory effect on protease activity and ions of Fe²⁺, Mg²⁺, Ca²⁺, Cu²⁺ and Ag⁺ caused enhancement of CMCase activity. The enzymes were stable not only towards the nonionic surfactants like Triton X-100 and Tween 80 but also the strong anionic surfactant, SDS. Moreover, the enzymes were not significantly inhibited by EDTA or cystein. Concerning biotechnological applications, the enzymes retained (51–97%) of their initial activities upon incubation in the presence of commercials detergents for 1 h. The potential use of the produced enzymes in the degradation of human hair and cotton fabric samples were also assessed.

Biochemical and molecular characterization of a serine keratinase from Brevibacillus brevis US575 with promising keratin-biodegradation and hide-dehairing activities

Dehairing is one of the highly polluting operations in the leather industry. The conventional lime-sulfide process used for dehairing produces large amounts of sulfide, which poses serious toxicity and disposal problems. This operation also involves hair destruction, a process that leads to increased chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solid (TSS) loads in the effluent. With these concerns in mind, enzyme-assisted dehairing has often been proposed as an alternative method. The main enzyme preparations so far used involved keratinases. The present paper reports on the purification of an extracellular keratinase (KERUS) newly isolated from Brevibacillus brevis strain US575. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer with a molecular mass of 29121.11 Da. The sequence of the 27 N-terminal residues of KERUS showed high homology with those of Bacillus keratinases. Optimal activity was achieved at pH 8 and 40°C. Its thermoactivity and thermostability were upgraded in the presence of 5 mM Ca²⁺. The enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP), which suggests that it belongs to the serine protease family. KERUS displayed higher levels of hydrolysis, substrate specificity, and catalytic efficiency than NUE 12 MG and KOROPON® MK EG keratinases. The enzyme also exhibited powerful keratinolytic activity that made it able to accomplish the entire feather-biodegradation process on its own. The kerUS gene encoding KERUS was cloned, sequenced, and expressed in Escherichia coli. The biochemical properties of the extracellular purified recombinant enzyme (rKERUS) were similar to those of native KERUS. Overall, the findings provide strong support for the potential candidacy of this enzyme as an effective and eco-friendly alternative to the conventional chemicals used for the dehairing of rabbit, goat, sheep and bovine hides in the leather processing industry.

Biotechnology of cold-active proteases

The bulk of Earth's biosphere is cold (<5 °C) and inhabited by psychrophiles. Biocatalysts from psychrophilic organisms (psychrozymes) have attracted attention because of their application in the ongoing efforts to decrease energy consumption. Proteinases as a class represent the largest category of industrial enzymes. There has been an emphasis on employing cold-active proteases in detergents because this allows laundry operations at ambient temperatures. Proteases have been used in environmental bioremediation, food industry and molecular biology. In view of the present limited understanding and availability of cold-active proteases with diverse characteristics, it is essential to explore Earth's surface more in search of an ideal cold-active protease. The understanding of molecular and mechanistic details of these proteases will open up new avenues to tailor proteases with the desired properties. A detailed account of the developments in the production and applications of cold-active proteases is presented in this review.

Draft genome sequence of Bacillus pumilus BA06, a producer of alkaline serine protease with leather-dehairing function

Bacillus pumilus BA06 was isolated from the proteinaceous soil and produced an extracellular alkaline protease with leather-dehairing function. The genome of BA06 was sequenced. The comparative genome analysis indicated that strain BA06 is different in genome from the other B. pumilus strains, with limited insertions, deletions, and rearrangements.

A new protease assay system using gelatin thin film for monitoring indoor air quality

Airborne particulates have a major influence on the quality of indoor environments, which in turn affects human health. Both allergens and proteases are major etiological factors in allergic disease. Thus, the monitoring of environmental protease particulates is very important for the management of allergic disease. Protease-monitoring systems have been introduced in industry, but have not been applied to domestic settings, probably because of the high cost and many complex steps involved in these systems. In this study, we developed an indoor protease-monitoring system which can easily detect protease particulates without need for pre-treatment of dust samples or complex measuring instruments such as fluorescent plate reader. As a protease substrate, gelatin thin film (GTF) was adopted to evaluate small amounts of house dust particulates. The principle of this assay is based on the hydrolysis of GTF. Protease molecules spread from a particulate to GTF can hydrolyze the gelatin, thereby producing a spot on the GTF. This hydrolyzed spot visualized by staining was much larger than the particulate size, making visible to naked eye. The GTF method facilitated the observation of a subtle increase in protease particulates fallen on the GTF after the turnover of a used bed-quilt. The newly developed GTF method seems to be a suitable tool for protease monitoring at home.

Production and characterization of alkaline protease from hemoglobin-degrading Bacillus pumilus NJM4 to produce fermented blood meal

The aim of the research was to isolate the hemoglobin-degrading bacterial strain to produce fermented blood meal and to characterize the protease produced by this strain. The strain NJM4, a kind of hemoglobin-degrading bacterial strain, was isolated by blood agar plates from slaughterhouse and identified as a Bacillus pumilus by physiological, biochemical, and morphological characteristics and by 16S rRNA gene sequencing. Bacillus pumilus NJM4 could degrade hemoglobin up to 85% in 36 h under the laboratory conditions. The optimal conditions for protease production was achieved at an initial pH level of 8.67, inoculum size of 4%, incubation temperature of 37 °C, and agitation rate 200 rpm. The optimum pH and temperature of hemoglobin-degrading proteases were at 9.0 and 50 °C, respectively. The protease activity was slightly decreased in presence of Ca(2+) and DTT. It was significantly inhibited in the presence of PMSF and EDTA identifying it as alkaline serine-metalloproteinase. Bacillus pumilus NJM4 and hemoglobin-degrading proteases provide potential use for biotechnological process of fermentation and enzymolysis blood meal as animal feed supplement.