Biochemical and structural characterization of a detergent-stable serine alkaline protease from seawater haloalkaliphilic bacteria

Efficacy of the Fruit and Vegetable Peels as Substrates for the Growth and Production of α-Amylases in Marine Actinobacteria

Enzymes from haloalkaliphilic microorganisms have recently focused attention on their potential and suitability in various applications. In this study, the growth and production of extracellular amylases in the marine actinomycetes, using kitchen waste as the raw starch source, have been investigated. Actinobacteria were isolated from the seawater of the Kachhighadi Coast near Dwarika, Gujarat. Seven Actinobacterial isolates of pre-monsoon, monsoon, and post-monsoon seasons belonging to different strains of Nocardiopsis genera were screened and selected for amylase production. The amylase production was initially assessed on the solid media supplemented with the extracts of different fruits and vegetable peels as a substrate by agar plate assay. The strains Kh-2(13), Kh-2(1), and Kh-3(12) produced maximum amylase with potato peel as a substrate, while no significant differences were found with the media containing other peels. Nevertheless, all strains produced amylases at a significant level with other raw substrates as well. For the optimization of the growth and enzyme production, the selected two isolates Kh-2(13) and Kh-3(12) of the monsoon and winter seasons were cultivated in a liquid medium under the submerged fermentation conditions, with potato peel as a substrate. In both organisms, the optimum amylase production was observed in the stationary phase of growth. For amylase production, the effect of different physical and chemical parameters was evaluated. The optimum growth and amylase production was achieved in 2% inoculum size, at pH 8.0, 28℃, and 5% salt concentration. On the basis of the amylase production index (API) (a ratio of the amylase units and cell growth), both isolates produced significant amylase with the only extract of potato peels, without any other supplements. The trends further indicated that while additional complex sources, such as yeast extract and peptone can enhance the cell growth of the actinobacteria, the amylase production remained unaltered. The study projects the significance of waste raw materials for the production of enzymes in extremophilic microorganisms.

Biochemical characterisation of a novel broad pH spectrum subtilisin from Fictibacillus arsenicus DSM 15822T

Subtilisins from microbial sources, especially from the Bacillaceae family, are of particular interest for biotechnological applications and serve the currently growing enzyme market as efficient and novel biocatalysts. Biotechnological applications include use in detergents, cosmetics, leather processing, wastewater treatment and pharmaceuticals. To identify a possible candidate for the enzyme market, here we cloned the gene of the subtilisin SPFA from Fictibacillus arsenicus DSM 15822T (obtained through a data mining-based search) and expressed it in Bacillus subtilis DB104. After production and purification, the protease showed a molecular mass of 27.57 kDa and a pI of 5.8. SPFA displayed hydrolytic activity at a temperature optimum of 80 °C and a very broad pH optimum between 8.5 and 11.5, with high activity up to pH 12.5. SPFA displayed no NaCl dependence but a high NaCl tolerance, with decreasing activity up to concentrations of 5 m NaCl. The stability enhanced with increasing NaCl concentration. Based on its substrate preference for 10 synthetic peptide 4-nitroanilide substrates with three or four amino acids and its phylogenetic classification, SPFA can be assigned to the subgroup of true subtilisins. Moreover, SPFA exhibited high tolerance to 5% (w/v) SDS and 5% H2 O2 (v/v). The biochemical properties of SPFA, especially its tolerance of remarkably high pH, SDS and H2 O2 , suggest it has potential for biotechnological applications.

Biocatalytic Profiling of Free and Immobilized Partially Purified Alkaline Protease from an Autochthonous Bacillus aryabhattai Ab15-ES

Partially purified alkaline protease produced by an indigenous bacterial strain, Bacillus aryabhattai Ab15-ES, was insolubilized in alginate beads using an entrapment technique. Maximum entrapped enzyme activities of 68.76% and 71.06% were recorded at optimum conditions of 2% (w/v) sodium alginate and 0.3 M calcium chloride. Biochemical profiling of free and immobilized proteases was investigated by determining their activity and stability as well as kinetic properties. Both enzyme preparations exhibited maximum activity at the optimum pH and temperature of 8.0 and 50 °C, respectively. However, in comparison to the free enzyme, the immobilized protease showed improved pH stability at 8.0–9.0 and thermal stability at 40–50 °C. In addition, the entrapped protease exhibited a higher Vmax and increased affinity to the substrate (1.65-fold) than the soluble enzyme. The immobilized protease was found to be more stable than the free enzyme, retaining 80.88% and 38.37% of its initial activity when stored at 4 °C and 25 °C, respectively, for 30 d. After repeated use seven times, the protease entrapped in alginate beads maintained 32.93% of its original activity. These findings suggest the efficacy and sustainability of the developed immobilized catalytic system for various biotechnological applications.

Screening, characterization, and kinetic studies of a serine alkaline protease from kitchen wastewater bacteria P2S1An and evaluation of its application in nutraceutical production

This present investigation aimed at characterizing the biochemical potential and kinetic study of the protease isolated from kitchen wastewater bacteria, P2S1An. The enzymatic activity was optimum when incubated for 96 h, at 30°C and pH 9.0. The enzymatic activity of the purified protease (PrA) was 10.47-folds that of crude protease (S1). PrA was about 35 kDa in molecular weight. The broad pH and thermal stability, chelators, surfactants and solvent tolerance, and favorable thermodynamics suggested the potentiality of the extracted protease PrA. Thermal activity and stability were enhanced in presence of 1-mM Ca²⁺ ion at high temperatures. The protease was a serine one as its activity was completely diminished in presence of 1-mM PMSF. The V_max , K_m , and K_cat /K_m suggested stability and catalytic efficiency of the protease. PrA hydrolyzes fish protein with 26.61 ± 0.16% of peptide bond cleavage after 240 min, comparable to Alcalase 2.4L (27.13 ± 0.31%). PRACTITIONER POINTS: A serine alkaline protease PrA was extracted from kitchen wastewater bacteria Bacillus tropicus Y14. Protease PrA showed significant activity and stability in a wide temperature and pH range. Protease showed great stability towards additives like metal ions, solvents, surfactants, polyols, and inhibitors. Kinetic study showed that the protease PrA had a prominent affinity and catalytic efficiency for the substrates. PrA hydrolysed fish proteins into short bioactive peptides which signify its potential in the formation of functional food ingredients.

A Novel κ-Carrageenase from Marine Bacterium Rhodopirellula sallentina SM41: Heterologous Expression, Biochemical Characterization and Salt-Tolerance Mechanism Investigation

κ-carrageenases are members of the glycoside hydrolase family 16 (GH16) that hydrolyze sulfated galactans in red algae, known as κ-carrageenans. In this study, a novel κ-carrageenase gene from the marine bacterium Rhodopirellula sallentina SM41 (RsCgk) was discovered via the genome mining approach. There are currently no reports on κ-carrageenase from the Rhodopirellula genus, and RsCgk shares a low identity (less than 65%) with κ- carrageenase from other genera. The RsCgk was heterologously overexpressed in Escherichia coli BL21 and characterized for its enzymatic properties. RsCgk exhibited maximum activity at pH 7.0 and 40 °C, and 50% of its initial activity was retained after incubating at 30 °C for 2 h. More than 70% of its activity was maintained after incubation at pH 6.0-8.0 and 4 °C for 24 h. As a marine derived enzyme, RsCgk showed excellent salt tolerance, retaining full activity in 1.2 M NaCl, and the addition of NaCl greatly enhanced its thermal stability. Mass spectrometry analysis of the RsCgk hydrolysis products revealed that the enzyme had high degradation specificity and mainly produced κ-carrageenan disaccharide. Comparative molecular dynamics simulations revealed that the conformational changes of tunnel-forming loops under salt environments may cause the deactivation or stabilization of RsCgk. Our results demonstrated that RsCgk could be utilized as a potential tool enzyme for efficient production of κ-carrageenan oligosaccharides under high salt conditions.

Purification, Characterization, and Application of Alkaline Protease Enzyme from a Locally Isolated Bacillus cereus Strain

Among the microbial enzymes protease and amylase are the most valuable enzymes which have been has diversified applications and used extensively because of their capabilities in the degradation of organic wastes, application in biofuels, agricultural, pharmaceuticals, chemical and biotechnological industries. The aim of the current research work was the purification, characterization and application of alkaline proteases extracted from Bacillus cereus AUST-7. Various concentrations of ammonium sulphate were applied for enzyme precipitation. Sephadex-G 100 was used in FPLC system for separation of protease from other proteins. SDS-PAGE was used to measure the molecular weight of required alkaline protease. Relative activities were determined against different pH, temperature, and incubation period to measure the enzymes activity. Stability of pH, temperature and various metal ions and inhibiter were also studied. Purified enzymes were applied on the goat skin to explore the dehairing efficacy. A 6.5 purification fold and 1163.50 U/mg of specific activity were obtained at 70% saturation and 35. 91 purification fold and 8902 U/mg of specific activity were observed after FPLC separation. The 35 kDa molecular size of protease enzyme was exhibited on the SDS-PAGE. The purified enzyme was stable at pH 10, temperature 55 °C and 35 min of incubation period. The purified enzyme was found to be stable at pH 8–11, thermo-stability at 50 °C and phenyl methyl sulphonyl fluoride (PMSF) and di-isopropyl fluorophosphates (DFP) inhibited the enzyme activity. The enzyme has good potential as dehairing agent in leather industries.

Biochemical characterization of a novel oxidatively stable, halotolerant, and high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101T

Halophilic and halotolerant microorganisms represent a promising source of salt-tolerant enzymes suitable for various biotechnological applications where high salt concentrations would otherwise limit enzymatic activity. Considering the current growing enzyme market and the need for more efficient and new biocatalysts, the present study aimed at the characterization of a high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101^T . The protease gene was cloned and expressed in Bacillus subtilis DB104. The recombinant protease SPAO with 269 amino acids belongs to the subfamily of high-alkaline subtilisins. The biochemical characteristics of purified SPAO were analyzed in comparison with subtilisin Carlsberg, Savinase, and BPN'. SPAO, a monomer with a molecular mass of 27.1 kDa, was active over a wide range of pH 6.0-12.0 and temperature 20-80 °C, optimally at pH 9.0-9.5 and 55 °C. The protease is highly oxidatively stable to hydrogen peroxide and retained 58% of residual activity when incubated at 10 °C with 5% (v/v) H₂ O₂ for 1 h while stimulated at 1% (v/v) H₂ O₂ . Furthermore, SPAO was very stable and active at NaCl concentrations up to 5.0 m. This study demonstrates the potential of SPAO for biotechnological applications in the future.

Purification and Characterization of Strong Simultaneous Enzyme Production of Protease and α-Amylase from an Extremophile-Bacillus sp. FW2 and Its Possibility in Food Waste Degradation

Microbial enzymes such as protease and amylase are valuable enzymes with various applications, widely investigated for their applications in degradation of organic waste, biofuel industries, agricultural, pharmaceuticals, chemistry, and biotechnology. In particular, extremophiles play an important role in biorefinery due to their novel metabolic products such as high value catalytic enzymes that are active even under harsh environmental conditions. Due to their potentials and very broad activities, this study isolated, investigated, and characterized the protease- and amylase-producing bacterial strain FW2 that was isolated from food waste. Strain FW2 belongs to the genus Bacillus and was found to be closest to Bacillus amyloliquefaciens DSM 7T with a similarity of 99.86%. This strain was able to degrade organic compounds at temperatures from −6 °C to 75 °C (but weak at 80 °C) under a wide pH range (4.5–12) and high-salinity conditions up to 35% NaCl. Maximum enzyme production was obtained at 1200 ± 23.4 U/mL for protease and 2400 ± 45.8 U/mL for amylase for 4 days at pH 7–7.5, 40–45 °C, and 0–10% NaCl. SDS-PAGE analysis showed that the molecular weights of purified protease were 28 kDa and 44 kDa, corresponding to alkaline protease (AprM) and neutral protease (NprM), respectively, and molecular weight of α-amylase was 55 kDa. Degradation food waste was determined after 15 days, observing a 69% of volume decrease. A potential commercial extremozyme-producing bacteria such as strain FW2 may be a promising contributor to waste degradation under extreme environmental conditions.

Understanding the Basis of Occurrence, Biosynthesis, and Implications of Thermostable Alkaline Proteases

The group of hydrolytic enzymes synonymously known as proteases is predominantly most favored for the class of industrial enzymes. The present work focuses on the thermostable nature of these proteolytic enzymes that occur naturally among mesophilic and thermophilic microbes. The broad thermo-active feature (40-80 °C), ease of cultivation, maintenance, and bulk production are the key features associated with these enzymes. Detailing of contemporary production technologies, and controllable operational parameters including the purification strategies, are the key features that justify their industrial dominance as biocatalysts. In addition, the rigorous research inputs by protein engineering and enzyme immobilization studies add up to the thermo-catalytic features and application capabilities of these enzymes. The work summarizes key features of microbial proteases that make them numero-uno for laundry, biomaterials, waste management, food and feed, tannery, and medical as well as pharmaceutical industries. The quest for novel and/or designed and engineered thermostable protease from unexplored sources is highly stimulating and will address the ever-increasing industrial demands.

Retracted: Production, biochemical characterization, and kinetic/thermodynamic study of novel serine protease from Aspergillus avenaceus URM 6706

"Production, biochemical characterization, and kinetic/thermodynamic study of novel serine protease from Aspergillus avenaceus URM 6706" (by da Silva A, et al.) Bio. Tech. Prog.; https://aiche.onlinelibrary.wiley.com/doi/10.1002/btpr.3091 The above listed article, from Biotechnology Progress, published online in Early View on October 16, 2020 in Wiley Online Library (http://wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal's Editor-in-Chief, John A. Morgan and Wiley Periodicals LLC. The retraction has been agreed because the article was not accepted for publication by the Journal and subsequently published in error as an Early View article. The editorial team of this journal takes full responsibility and apologizes for the technical error that resulted in this article appearing in Early View.

Protease from Mucor subtilissimus UCP 1262: Evaluation of several specific protease activities and purification of a fibrinolytic enzyme

The industrial demand for proteolytic enzymes is stimulating the search for new enzyme sources. Fungal enzymes are preferred over bacterial enzymes, and more effective and easier to extract. The aim of this work was to evaluate the potential of protease production by solid state fermentation (SSF) of Mucor subtilissimus UCP 1262, evaluate different specific activities, purify and partially characterize the enzyme in terms of biochemical as to the optimal pH and temperature. Initially, the enzyme crude extract was screened for 3 different proteolytic activities, collagenolytic (161.4 U/mL), keratinolytic (39.6 U/mL) and fibrinolytic (26.1 U/mL) in addition to conventional proteinase activity. After ammonium sulfate precipitation, the active fractions with fibrinolytic activity were dialyzed in 15 mM Tris-HCl buffer, pH 8, loaded onto DEAE-Sephadex A50 ion-exchange column and gel filtrated through Superdex 75 HR10/300. The enzyme showed a fibrinolytic maximum activity at 40 C and pH 9,0. The purified enzyme showed activity against a chromogenic chymotrypsin substrate, SDS-PAGE showing a molecular mass of approximately 70 kDa and, the specific activity of 25.93 U/mg. These characteristics suggest that the enzyme could be and efficiently produced in a simple and low-cost way using Mucor subtilissimus UCP 1262 in SSF.

Virgibacillus halodenitrificans ST-1 for fermentation of shrimp paste and hydrolysates of its protease

The nutrition and flavor of shrimp paste came from hydrolyzation by enzymes that were produced by microorganisms. The salt-tolerant strain Virgibacillus halodenitrificans ST-1 isolated from shrimp paste was studied and used in the fermentation of shrimp paste. The strain and the protease produced by ST-1 were investigated. The optimum pH of the protease was 8.0, and the reaction temperature was 30°C. The protease showed high activity in the range of pH (5.0-11.0) and NaCl concentration (1%-15%). Divalent cations such as Ba2+, Ca2+, Mg2+, Mn2+, and Si2+ could enhance the protease activity. Residual activity of protease was more than 90% when it was incubated with PMSF and H2O2. Also, the enzyme retained more than 90% of initial activity after it was incubated with organic solvents. Variety of natural proteins could be substrates of the protease. By analyzing the release rate of free amino acids, it was predicted that the cleavage sites of the protease were mainly Glu, Asp, Gly, Leu, and Lys. Moreover, the hydrolysates of the protease had antioxidant activity, especially for DPPH and superoxide anion radical scavenging. The strain ST-1 and the protease both were excellent candidates for food industries.

Cloning, Expression, and Structural Elucidation of a Biotechnologically Potential Alkaline Serine Protease From a Newly Isolated Haloalkaliphilic Bacillus lehensis JO-26

An alkaline protease gene of Bacillus lehensis JO-26 from saline desert, Little Rann of Kutch, was cloned and expressed in Escherichia coli BL21 (DE3). A 1,014-bp ORF encoded 337 amino acids. The recombinant protease (APrBL) with Asp 97, His 127, and Ser 280 forming catalytic triad belongs to the subtilase S8 protease family. The gene was optimally expressed in soluble fraction with 0.2 mM isopropyl β-D-thiogalactopyranoside (IPTG), 2% (w/v) NaCl at 28°C. APrBL, a monomer with a molecular mass of 34.6 kDa was active over pH 8–11 and 30°C−70°C, optimally at pH 10 and 50°C. The enzyme was highly thermostable and retained 73% of the residual activity at 80°C up to 3 h. It was significantly stimulated by sodium dodecyl sulfate (SDS), Ca²⁺, chloroform, toluene, n-butanol, and benzene while completely inhibited by phenylmethylsulfonyl fluoride (PMSF) and Hg²⁺. The serine nature of the protease was confirmed by its strong inhibition by PMSF. The APrBL gene was phylogenetically close to alkaline elastase YaB (P20724) and was distinct from the well-known commercial proteases subtilisin Carlsberg (CAB56500) and subtilisin BPN′ (P00782). The structural elucidation revealed 31.75% α-helices, 22.55% β-strands, and 45.70% coils. Although high glycine and fewer proline residues are a characteristic feature of the cold-adapted enzymes, the similar observation in thermally active APrBL suggests that this feature cannot be solely responsible for thermo/cold adaptation. The APrBL protease was highly effective as a detergent additive and in whey protein hydrolysis.

Biochemical, thermodynamic and structural characteristics of a biotechnologically compatible alkaline protease from a haloalkaliphilic, Nocardiopsis dassonvillei OK-18

This report describes purification strategies, biochemical properties and thermodynamic analysis of an alkaline serine protease from a marine actinomycete, Nocardiopsis dassonvillei strain OK-18. The solvent tolerance, broad thermal-pH stability, favourable kinetics and thermodynamics suggest stability of the enzymatic reaction. The enzyme was active in the range of pH 7-12 and 37-90 °C, optimally at pH 9 and 70 °C. The deactivation rate constant (Kd), half-life (t½), enthalpy (ΔH*), entropy (ΔS*), activation energy (E) and change in free energy (ΔG*) suggested stability and spontaneity of the reaction. β-Sheets as revealed by the Circular dichroism (CD) spectroscopy, were the major elements in the secondary structure of the enzyme, while Fourier-transform infrared spectroscopy (FTIR) indicated the presence of amide I and amide II. Based on the liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) analysis, the amino acid sequence had only 38% similarity with other proteases of Nocardiopsis strains, suggesting its novelty. The Ramachandran Plot revealed the location of the amino acid residues in the most favored region. The blood de-staining, gelatin hydrolysis, silver recovery and deproteinization of crab shells established the biotechnological potential of the enzyme.

Deep Hypersaline Anoxic Basins as Untapped Reservoir of Polyextremophilic Prokaryotes of Biotechnological Interest

Deep-sea hypersaline anoxic basins (DHABs) are considered to be among the most extreme ecosystems on our planet, allowing only the life of polyextremophilic organisms. DHABs’ prokaryotes exhibit extraordinary metabolic capabilities, representing a hot topic for microbiologists and biotechnologists. These are a source of enzymes and new secondary metabolites with valuable applications in different biotechnological fields. Here, we review the current knowledge on prokaryotic diversity in DHABs, highlighting the biotechnological applications of identified taxa and isolated species. The discovery of new species and molecules from these ecosystems is expanding our understanding of life limits and is expected to have a strong impact on biotechnological applications.

Identification of a New Serine Alkaline Peptidase from the Moderately Halophilic Virgibacillus natechei sp. nov., Strain FarDT and its Application as Bioadditive for Peptide Synthesis and Laundry Detergent Formulations

A new peptidase designated as SAPV produced from a moderately halophilic Virgibacillus natechei sp. nov., strain FarDT was investigated by purification to homogeneity followed by biochemical and molecular characterization purposes. Through optimization, it was determined that the optimum peptidase activity was 16,000 U/mL. It was achieved after 36 h incubation at 35°C in the optimized enzyme liquid medium (ELM) at pH 7.4 that contains only white shrimp shell by-product (60 g/L) as sole energy and carbon sources. The SAPV enzyme is a monomer protein with a molecular mass of 31 kDa as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance liquid chromatography (HPLC) gel filtration chromatography. The sequence of its NH2-terminal amino-acid residues showed homology with those of Bacillus peptidases S8/S53 superfamily. The SAPV showed optimal activity at pH 9 and 60°C. Irreversible inhibition of enzyme activity by diiodopropyl fluorophosphates (DFP) and phenylmethanesulfonyl fluoride (PMSF) confirmed its belonging to the serine peptidases. Considering its interesting biochemical characterization, the sapV gene was cloned, sequenced, and heterologously overexpressed in the extracellular fraction of E. coli BL21(DE3)pLysS. The biochemical properties of the recombinant peptidase (rSAPV) were similar to those of the native one. The highest sequence identity value (97.66%) of SAPV was obtained with peptidase S8 from Virgibacillus massiliensis DSM 28587, with 9 amino-acid residues of difference. Interestingly, rSAPV showed an outstanding and high resistance to several organic solvents than SPVP from Aeribacillus pallidus VP3 and Thermolysin type X. Furthermore, rSAPV exhibited an excellent detergent stability and compatibility than Alcalase 2.4 L FG and Bioprotease N100L. Considering all these remarkable properties, rSAPV has attracted the interest of industrialists.

Alkaline serine protease from the new halotolerant alkaliphilic Salipaludibacillus agaradhaerens strain AK-R: purification and properties

Herein, we report the purification and characterization of an alkaline protease from the alkaliphilic Salipaludibacillus agaradhaerens (formerly Bacillus agaradhaerens) strain AK-R, which was previously isolated from Egyptian soda lakes. The purification procedures resulted in enzyme purification up to 13.3-fold, with a recovery yield of 16.3% and a specific activity of 3488 U/mg protein. AK-R protease was a monomeric protein with an estimated molecular weight of 33.0 kDa. The optimum pH and temperature for AK-R protease were pH 10 and 60 °C, respectively. The enzyme thermostability was significantly enhanced in the presence of CaCl₂ by approximately 1.3-fold. Moreover, under optimal conditions, the K _m and V _max values of the enzyme were 2.63 mg/ml and 4166.7 U/mg, respectively. PMSF caused complete inhibition of the enzyme activity, suggesting that AK-R belongs to the serine protease family. In addition, the enzyme was completely inhibited by EDTA, revealing the requirement of metal ions for AK-R protease activity; hence, it can be classified as a metalloprotease. AK-R protease is a mostly thiol-independent enzyme, since thiol reductants such as β-mercaptoethanol and dithiothreitol had no effect on the enzyme activity. AK-R protease exhibited high stability in several organic solvents, including butanol, amyl alcohol, dimethyl ether, toluene, diethyl ether and methanol. Moreover, AK-R protease showed significant stability to a variety of surfactants and commercial detergents. The features and properties of AK-R alkaline protease are favourable and suggest its potential applications in various industries, particularly in the laundry detergent industry.

Characterization and biotechnological application of protease from thermophilic Thermomonas haemolytica

In this study, it was aimed to determine the ability to produce protease enzyme of Thermomonas haemolytica isolated from geothermal Nenehatun hot spring in Turkey and utilization of this enzyme in the detergent industry to remove protein stains. The protease-producing strains were screened from hot springs, and a potential strain was identified as T. haemolytica according to morphological, physiological and biochemical characteristics and sequence of 16S rRNA gene. Maximum protease activity was observed at 55 °C and pH 9.0 at 72 h of incubation. Activity was very stable between 50 and 65 °C and pH 8.0-10.0, respectively. The enzyme activity was significantly inhibited by PMSF and partly inhibited by EDTA, EGTA, SDS, and urea. Some divalent metal ions such as Ca²⁺, Mg²⁺, and Mn²⁺ increased the enzyme activity, while Zn²⁺ and Cu²⁺ decreased. Michaelis-Menten constant (K_m) and maximum velocity (V_max) values were calculated by Lineweaver-Burk plot as 125 EU/ml and 1262 mg/ml, respectively. The biochemical characterization of the protease obtained from T. haemolytica was performed and applied on the blood and grass-stained fabrics with detergent to evaluate the stain removal performance of the enzyme. It was observed that the application of detergent with enzyme was more effective than the detergent without enzyme to clean up the stained fabrics. This is the first report of characterization of the protease of T. haemolytica. According to results obtained from this study, this new strain is a promising candidate for industrial applications in production of detergent.

Trends in extracellular serine proteases of bacteria as detergent bioadditive: alternate and environmental friendly tool for detergent industry

Proteases, one of the largest groups of industrial enzymes occupy a major share in detergent industry. To meet the existing demands, proteases with efficient catalytic properties are being explored from bacteria residing in extreme habitats. Alkaline proteases are also considered as promising candidates for industrial sectors due to the activity and stability under alkaline and harsh environment. Therefore, a systematic review on experimental studies of bacterial proteases was conducted with emphasis on purification, characterization, cloning and expression and their suitability as detergent additive. Relevant searches using a combination of filters/keywords were performed in the online databases; PubMed, Science Direct, Scopus and Web of Science. Over thousands of research papers, 71 articles in Scopus, 48 articles in Science Direct, 18 articles in PubMed and 8 articles in Web of Science were selected with regard to bacterial extracellular proteases till date. Selected articles revealed majority of the studies conducted between the years 2015 and 17 and were focused on purification of proteases from bacteria. Among microbes, a total of 41 bacterial genera have been explored with limited studies from extreme habitats. Majority of the studies have reported the involvement of subtilisin-like serine proteases with effective properties for detergent industries. The studies revealed shifting of trend from purification to cloning to genetic engineering to meet the industrial demands. The present systematic review describes the proteases from extremophilic bacteria and use of biotechnological techniques such as site-directed mutagenesis and codon optimization to engineer enzymes with better hot spots in the active sites to meet industrial challenges.

Purification, Characterization and Thermodynamic Assessment of an Alkaline Protease by Geotrichum Candidum of Dairy Origin

Background

Alkaline proteases is the important group of enzymes having numerous industrial applications including dairy food formulations.

Objectives

The current study deals with the purification and characterization of an alkaline serine protease produced by Geotrichum candidum QAUGC01, isolated from indigenous fermented milk product, Dahi.

Material and Methods

In total twelve G. candidum strains were screened for their proteolytic activity by using standard protease assay. The protease production from G. candidum QAUGC01 was optimized by varying physio-chemical conditions. The protease was purified by using two-step method: ammonium sulfate precipitation and gel filtration chromatography. Protease was further characterized by studying various parameter like temperature, pH, modulators, metal ions and organic solvent. A thermodynamic study was also carried out to explore the half-life of protease.

Results

The G. candidum grew profusely at 25 °C and at an initial pH of 4.0 for 72 h of incubation producing 26.21 U/ml maximum extracellular protease. Protease revealed that V_max and K_m was 26.25 U.ml^-1.min^-1 and 0.05 mg.mL^-1, respectively using casein as substrate. The enzyme was stable at a temperature range (25-45 °C) and pH (8-9). Residual enzyme activity was strongly inhibited in the presence of PMSF (7.5%). The protease could hydrolyze proteinaceous substrates, casein (98%) and BSA (95%). The thermodynamic studies explored that the half-life of the enzyme that was 106.62 min, 38.72 min and 15.71 min at 50, 60 and 70 °C, respectively.

Conclusions

Purified protease from G. candidum GCQAU01 is an ideal candidate for industrial application.

Purification and characterization of a novel extracellular serine-protease with collagenolytic activity from Aspergillus tamarii URM4634

An extracellular serine-protease from Aspergillus tamarii URM4634 was purified and characterized. The possibility of using Aspergillus tamarii URM4634 protease in detergent formulations and collagenolytic activity was investigated. The protease demonstrated excellent stability at pH range 7.0-11.0, the optimum being at pH 9.0. The enzyme was stable at 40 °C for 180 min, enhanced by Mg⁺⁺ and Ca⁺⁺, but inhibited by Zn⁺⁺, and strongly inhibited by phenylmethylsulfonyl fluoride (PMSF), suggested as serine-protease. The azocasein substrate result showed Km = 0.434 mg/mL and V_max = 7.739 mg/mL/min. SDS-PAGE and azocasein zymography showed that the purified alkaline protease (2983.8 U/mg) had a molecular mass of 49.3 kDa. The enzyme was purified by column chromatography using Sephadex A50 resin. The proteolytic activity was activated by SDS (sodium dodecyl sulfate), Tween-80, Tween 20 and Triton-100. This study demonstrated that A. tamarii URM4634 protease has potent, stable and compatible collagenolytic activity to the desired level in local laundry detergent brands compared with similar enzymes produced by solid-state fermentation. This protease can thus be chosen as an option in both the food industry to tenderization meat and the detergent industry to washing process.

Phylogeny, novel bacterial lineage and enzymatic potential of haloalkaliphilic bacteria from the saline coastal desert of Little Rann of Kutch, Gujarat, India

This report describes cultivation-dependent diversity, phylogeny and enzymatic potential of the haloalkaliphilic bacteria isolated from the unvegetated desert soil of yet unexplored, saline desert of Little Rann of Kutch (LRK), India. The LRK is a unique ecosystem displaying a combination of Dry Rann and Wet Rann. A total of 25 bacteria were isolated and characterized on the basis of colony morphology, biochemical profile, sugar utilization, secretion of the extracellular enzymes and antibiotic sensitivity. Further, the identification and phylogenetic relatedness of 23 bacteria were established by the analysis of 16S rRNA gene sequences. The phylogenetic analysis indicated that the isolates belong to the phylum Firmicutes, comprising low G + C, Gram-positive bacteria, with different genera: Bacillus (~ 39%), Staphylococcus (~ 30%), Halobacillus (~ 13%), Virgibacillus (~ 13%), Oceanobacillus (~ 4%). Majority of the bacterial isolates produced proteases (30% isolates) followed by cellulases (24% isolates), CMCases (24% isolates) and amylases (20% isolates). Halobacillus, Virgibacillus and Bacillus predominantly produced hydrolases, while many produced multiple enzymes at high salinity and alkaline pH. Highest antibiotic resistance was observed against Ampicillin and Penicillin (32%) followed by Cefaclor (20%); Colistin, Cefoperazone and Cefotaxime (16%); Cefuroxime (12%); Gentamycin and Cefixime (8%); Erythromycin, Cefadroxil, Azithromycin, Co-trimoxazole, Amoxycillin, Norfloxacin, Cefpodoxime, Amikacin and Augmentin (4%). KJ1-10-99 and KJ1-10-93 representing < 97% of 16S rRNA gene sequence similarity belong to a novel lineage within the family Bacillaceae. Comparison of the phenogram and phylogram revealed the contradiction of the phenogram pattern and the phylogenetic placement of the isolates. The isolates belonging to same species have shown considerable phenotypic variation. The study on the cultivable haloalkaliphilic bacteria of an unexplored enigmatic niche reflects ecological and biotechnological significance.

Proteolytic and amylolytic enzymes from a newly isolated Bacillus mojavensis SA: Characterization and applications as laundry detergent additive and in leather processing

The present work aims to study the simultaneous production of highly alkaline proteases and thermostable α-amylases by a newly isolated bacterium Bacillus mojavensis SA. The optimum pH and temperature of amylase activity were 9.0 and 55°C, respectively, while those of the proteolytic activity were 12.0 and 60°C, respectively. Both α-amylase and protease enzymes showed a high stability towards a wide range of pH and temperature. Furthermore, SA crude enzymes were relatively stable towards non-ionic (Tween 20, Tween 80 and Triton X-100) and anionic (SDS) surfactants, as well as oxidizing agents. Both activities were improved by the presence of polyethylene glycol 4000 and glycerol. Additionally, the crude enzymes showed excellent stability against various solid and liquid detergents. Wash performance analysis revealed that the SA crude enzymes exhibited a remarkable efficiency in the removal of a variety type of stains, such as blood, chocolate, coffee and oil. On the other side, SA proteases revealed a potential dehairing activity of animal hide without chemical assistance or fibrous proteins hydrolysis. Thus, considering their promising properties, B. mojavensis SA crude enzymes could be used in several biotechnological bioprocesses.

Desertibacillus haloalkaliphilus gen. nov., sp. nov., isolated from a saline desert

Two Gram-stain-positive, rod-shaped and endospore-forming bacteria that represent a single species, designated strains KJ1-10-99^T and KJ1-10-93, were isolated from a saline desert of Little Rann of Kutch, Gujarat, India. Analysis of 16S rRNA gene sequences revealed that the isolates belonged to the family Bacillaceae and were closely related to each other with 16S rRNA gene sequence similarity of 99.9 %. However, these two isolates formed a novel phylogenetic branch within this family. Both strains were aerobic, catalase and oxidase positive, and could grow optimally at 37 °C and pH 9. Further, strains KJ1-10-99^T and KJ1-10-93 grew optimally at a NaCl concentration of 7.5 and 15 % (w/v), respectively. Both strains shared highest sequence similarity with Fermentibacillus polygoni IEB3^T (96.90 %) followed by Bacillus nanhaiisediminis NH3^T (96.3 %) and Bacillus alkalinitrilicus ANL-iso4^T (96.3 %). The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17:0, C16 : 0, and iso-C15 : 0. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol in both strains. The predominant isoprenoid quinone was MK-7 in both the strains. The peptidoglycan contained meso-diaminopimelic acid (meso-DAP) as the diagnostic diamino acid. The DNA G+C content of strains KJ1-10-99^T and KJ1-10-93 were 48.7 and 48.9 mol% respectively. Both strains could be distinguished from closest phylogenetic neighbours based on a number of phenotypic properties. On the basis of polyphasic taxonomic analysis and phylogenetic data, we conclude that the strains KJ1-10-99^T (=LMG 29918^T=KCTC 33878^T) and KJ1-10-93 (=LMG 29919=KCTC 33877) represent a novel species of a new genus in the family Bacillaceae, order Bacillales, for which the name Desertibacillus haloalkaliphilus gen. nov., sp. nov. is proposed.

Detergent-compatible, organic solvent-tolerant alkaline protease from Bacillus circulans MTCC 7942: Purification and characterization

Proteases are now recognized as the most indispensable industrial biocatalyst owing to their diverse microbial sources and innovative applications. In the present investigation, a thermostable, organic solvent-tolerant, alkaline serine protease from Bacillus circulans MTCC 7942, was purified and characterized. The protease was purified to 37-fold by a three-step purification scheme with 39% recovery. The optimum pH and temperature for protease was 10 and 60 °C, respectively. The apparent molecular mass of the purified enzyme was 43 kD as revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The Km and Vmax values using casein-substrate were 3.1 mg/mL and 1.8 µmol/min, respectively. The protease remained stable in the presence of organic solvents with higher (>3.2) log P value (cyclohexane, n-octane, n-hexadecane, n-decane, and n-dodecane), as compared to organic solvents with lower (<3.2) log P value (acetone, butanol, benzene, chloroform, toluene). Remarkably, the protease showed profound stability even in the presence of organic solvents with less log P values (glycerol, dimethyl sulfate [DMSO], p-xylene), indicating the possibility of nonaqueous enzymatic applications. Also, protease activity was improved in the presence of metal ions (Ca(2+), Mg(2+), Mn(2+)); enhanced by biosurfactants; hardly affected by bleaching agents, oxidizing agents, and chemical surfactants; and stable in commercial detergents. In addition, a protease-detergent formulation effectively washed out egg and blood stains as compared to detergent alone. The protease was suitable for various commercial applications like processing of gelatinous film and as a compatible additive to detergent formulation with its operative utility in hard water.

Recent Advances in Marine Enzymes for Biotechnological Processes

In the last decade, new trends in the food and pharmaceutical industries have increased concern for the quality and safety of products. The use of biocatalytic processes using marine enzymes has become an important and useful natural product for biotechnological applications. Bioprocesses using biocatalysts like marine enzymes (fungi, bacteria, plants, animals, algae, etc.) offer hyperthermostability, salt tolerance, barophilicity, cold adaptability, chemoselectivity, regioselectivity, and stereoselectivity. Currently, enzymatic methods are used to produce a large variety of products that humans consume, and the specific nature of the enzymes including processing under mild pH and temperature conditions result in fewer unwanted side-effects and by-products. This offers high selectivity in industrial processes. The marine habitat has been become increasingly studied because it represents a huge source potential biocatalysts. Enzymes include oxidoreductases, hydrolases, transferases, isomerases, ligases, and lyases that can be used in food and pharmaceutical applications. Finally, recent advances in biotechnological processes using enzymes of marine organisms (bacterial, fungi, algal, and sponges) are described and also our work on marine organisms from South America, especially marine-derived fungi and bacteria involved in biotransformations and biodegradation of organic compounds.

Biochemical and molecular characterization of new keratinoytic protease from Actinomadura viridilutea DZ50

A new extracellular thermostable keratinolytic protease, designated KERDZ, was purified and characterized from a thermophilic actinomycetes Actinomadura viridilutea DZ50 isolated from Algerian fishing port. The isolate exhibited high keratinase production when grown in chicken-feather meal media (18,000U/ml) after 96-h of incubation at 45°C. The enzyme was purified by ammonium sulfate precipitation (35-55%)-dialysis and heat treatment (30min at 75°C) followed by UNO S-1 FPLC cation exchange chromatography and size exclusion HPLC column. The biochemical characterizations carried on include physico-chemical determination and spectroscopic analysis. The MALDI-TOF/MS analysis revealed that the purified enzyme was a monomer with a molecular mass of 19536.10-Da. The sequence of the 25 N-terminal residues of KERDZ showed high homology with those of actinomycetes keratinases. Optimal activity was achieved at pH 11 and 80°C. KERDZ was completely inhibited by PMSF and DFP suggested its belonging to the serine keratinase family. KERDZ displayed higher levels of hydrolysis and catalytic efficiency than bacterial keratinases (KERAK-29, Actinase E, and KERAB) and subtilisins (subtilisin Carlsberg and subtilisin Novo). The kerDZ gene encoding KERDZ was isolated and its DNA sequence was determined. These properties make KERDZ a potential, promising and eco-friendly alternative to the conventional chemicals used for industrial applications.

A novel organic solvent- and detergent-stable serine alkaline protease from Trametes cingulata strain CTM10101

A protease-producing fungus was isolated from an alkaline wastewater of chemical industries and identified as Trametes cingulata strain CTM10101 on the basis of the ITS rDNA gene-sequencing. It was observed that the fungus strongly produce extracellular protease grown at 30°C in potato-dextrose-broth (PDB) optimized media (13500U/ml). The pure serine protease isolated by Trametes cingulata (designated SPTC) was purified by ammonium sulfate precipitation-dialysis followed by heat-treatment and UNO S-1 FPLC cation-exchange chromatography. The chemical characterization carried on include phisico-chemical determination and spectroscopie analysis. The MALDI-TOF/MS analysis revealed that the purified enzyme was a monomer with a molecular mass of 31405.16-Da. The enzyme had an NH2-terminal sequence of ALTTQTEAPWALGTVSHKGQAST, thus sharing high homology with those of fungal-proteases. The optimum pH and temperature values of its proteolytic activity were pH 9 and 60°C, respectively, and its half-life times at 60 and 70°C were 9 and 5-h, respectively. It was completely inhibited by PMSF and DFP, which strongly suggested its belonging to the serine protease family. Compared to Flavourzyme(®)500L from Aspergillus oryzae and Thermolysin typeX from Geobacillus stearothermophilus, SPTC displayed higher levels of hydrolysis, substrate specificity, and catalytic efficiency as well as elevated organic solvent tolerance and considerable detergent stability. Finally, SPTC could potentially be used in peptide synthesis and detergent formulations.

Production, purification and characterization of a thermotolerant alkaline serine protease from a novel species Bacillus caseinilyticus

Alkaline proteases are important enzymes in many industrial applications, especially as additives in laundry detergent industry. Though there are a number of Bacillus species which are reported to be producing proteases, the efficiency of a protease produced by a novel strain has to be studied in comparison to the others. Hence, in this study, an alkaline serine protease produced by a novel species Bacilluscaseinilyticus was purified and characterized for its possible usage in detergent industry. Ammonium sulphate, dialysis and DEAE column chromatographic methods were used for purification of the isolated alkaline protease. The molecular weight of the protease was determined by SDS-PAGE and it was found to be 66 kDa. Peptide mass fingerprinting (PMF) was carried out using MALDI-TOF-TOF mass spectrometry and the peptides were found to be similar to that of subtilisin protease. Specific activity of purified protein was found to be 89.2 U/mg. Optimum pH and temperature for enzyme activity were at pH 8 and 60 °C, respectively, showing stability with 10 mM CaCl₂. Phenyl methyl sulphonyl fluoride (PMSF) at both 5 and 10 mM concentrations completely inhibited the enzyme activity suggesting its serine nature. EDTA, metal ions Mg²⁺ and Ca²⁺ increased the enzyme activity. The one factor at a time optimisation of the protease production was carried to identify the important factors that affect its production. After optimisation, the protease was produced at lab scale, purified and characterised. This alkali, thermotolerant serine protease was found to be significantly stable in the presence of various surfactants and H₂O_2. Also, it was successfully able to remove blood stain when used as an additive along with commercial detergent suggesting its potential application in the laundry detergent industry.

Purification and characterization of an extracellular haloalkaline serine protease from the moderately halophilic bacterium, Bacillus iranensis (X5B)

This study reports the purification and characterization of an extracellular haloalkaline serine protease from the moderately halophilic bacterium, Bacillus iranensis, strain X5B. The enzyme was purified to homogeneity by acetone precipitation, ultrafiltration and carboxymethyl (CM) cation exchange chromatography, respectively. The purified protease was a monomeric enzyme with a relative molecular mass of 48-50 kDa and it was inhibited by PMSF indicating that it is a serine-protease. The optimum pH, temperature and NaCl concentration were 9.5, 35 °C and 0.98 M, respectively. The enzyme showed a significant tolerance to salt and alkaline pH. It retained approximately 50% of activity at 2.5 M NaCl and about 70% of activity at highly alkaline pH of 11.0; therefore, it was a moderately halophilic and also can be activated by metals, especially by Ca(2+). The specific activity of the purified protease was measured to be 425.23 μmol of tyrosine/min per mg of protein using casein as a substrate. The apparent K m and V max values were 0.126 mM and 0.523 mM/min, respectively and the accurate value of k cat was obtained as 3.284 × 10(-2) s(-1). These special and important characteristics make this serine protease as valuable tool for industrial applications.

Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease

While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth) was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production.

Detergent-, solvent- and salt-compatible thermoactive alkaline serine protease from halotolerant alkaliphilic Bacillus sp. NPST-AK15: purification and characterization

Alkaline protease produced by the halotolerant alkaliphilic Bacillus sp. strain NPST-AK15 was purified to homogeneity by the combination of ammonium sulfate precipitation, anion-exchange and gel permeation chromatography. The purified enzyme was a monomeric protein with an estimated molecular weight of 32 kDa. NPST-AK15 protease was highly active and stable over a wide pH range, with a maximal activity at pH 10.5. The enzyme showed optimum activity at 60 °C and was stable at 30-50 °C for at least 1 h. Thermal stability of the purified protease was substantially improved by CaCl2 (1.1- to 6.6-fold). The K m, V max and k cat values for the enzyme were 2.5 mg ml(-1), 42.5 µM min(-1) mg(-1), and 392.46 × 10(3) min(-1), respectively. NPST-AK15 protease activity was strongly inhibited by PMSF, suggesting that the enzyme is a serine protease. The enzyme was highly stable in NaCl up to 20 % (w/v). Moreover, the purified enzyme was stable in several organic solvents such as diethyl ether, benzene, toluene, and chloroform. In addition, it showed high stability and compatibility with a wide range of surfactants and commercial detergents and was slightly activated by hydrogen peroxide. These features of NPST-AK15 protease make this enzyme a promising candidate for application in the laundry and pharmaceutical industries.