Characterization of a Novel Surfactant and Organic Solvent Stable High-alkaline Protease from New Bacillus pseudofirmus SVB1

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.

Catalytic esterification performance of protease in micro-aqueous system

OBJECTIVE

To evaluate the catalytic esterification performance of proteases in micro-aqueous systems and to study the suitable conditions for maintaining protease activity.

RESULTS

It was found that the protease showed better enzyme catalytic activity in the micro-aqueous phase containing 4% boric acid-borax buffer than that of the pure organic phase. The protease activity was easily activated by 0.20 M boric acid-borax buffer, and the enzyme activity was still high for a long time in alkaline environment (pH 8.40-9.60) and under the temperature of 40-55 °C. Experiments using protease and Candida lipase to synthesize sucrose-6-ethyl ester showed that protease had better esterification activity than Candida lipase in the micro-aqueous phase.

Alkaliphiles: The Versatile Tools in Biotechnology

The extreme environments within the biosphere are inhabited by organisms known as extremophiles. Lately, these organisms are attracting a great deal of interest from researchers and industrialists. The motive behind this attraction is mainly related to the desire for new and efficient products of biotechnological importance and human curiosity of understanding nature. Organisms living in common "human-friendly" environments have served humanity for a very long time, and this has led to exhaustion of the low-hanging "fruits," a phenomenon witnessed by the diminishing rate of new discoveries. For example, acquiring novel products such as drugs from the traditional sources has become difficult and expensive. Such challenges together with the basic research interest have brought the exploration of previously neglected or unknown groups of organisms. Extremophiles are among these groups which have been brought to focus and garnering a growing importance in biotechnology. In the last few decades, numerous extremophiles and their products have got their ways into industrial, agricultural, environmental, pharmaceutical, and other biotechnological applications.Alkaliphiles, organisms which thrive optimally at or above pH 9, are one of the most important classes of extremophiles. To flourish in their extreme habitats, alkaliphiles evolved impressive structural and functional adaptations. The high pH adaptation gave unique biocatalysts that are operationally stable at elevated pH and several other novel products with immense biotechnological application potential. Advances in the cultivation techniques, success in gene cloning and expression, metabolic engineering, metagenomics, and other related techniques are significantly contributing to expand the application horizon of these remarkable organisms of the 'bizarre' world. Studies have shown the enormous potential of alkaliphiles in numerous biotechnological applications. Although it seems just the beginning, some fantastic strides are already made in tapping this potential. This work tries to review some of the prominent applications of alkaliphiles by focusing such as on their enzymes, metabolites, exopolysaccharides, and biosurfactants. Moreover, the chapter strives to assesses the whole-cell applications of alkaliphiles including in biomining, food and feed supplementation, bioconstruction, microbial fuel cell, biofuel production, and bioremediation.

Microbial Proteases Applications

The use of chemicals around the globe in different industries has increased tremendously, affecting the health of people. The modern world intends to replace these noxious chemicals with environmental friendly products for the betterment of life on the planet. Establishing enzymatic processes in spite of chemical processes has been a prime objective of scientists. Various enzymes, specifically microbial proteases, are the most essentially used in different corporate sectors, such as textile, detergent, leather, feed, waste, and others. Proteases with respect to physiological and commercial roles hold a pivotal position. As they are performing synthetic and degradative functions, proteases are found ubiquitously, such as in plants, animals, and microbes. Among different producers of proteases, Bacillus sp. are mostly commercially exploited microbes for proteases. Proteases are successfully considered as an alternative to chemicals and an eco-friendly indicator for nature or the surroundings. The evolutionary relationship among acidic, neutral, and alkaline proteases has been analyzed based on their protein sequences, but there remains a lack of information that regulates the diversity in their specificity. Researchers are looking for microbial proteases as they can tolerate harsh conditions, ways to prevent autoproteolytic activity, stability in optimum pH, and substrate specificity. The current review focuses on the comparison among different proteases and the current problems faced during production and application at the industrial level. Deciphering these issues would enable us to promote microbial proteases economically and commercially around the world.

Purification and characterization of a thermo- and organic solvent-tolerant alkaline protease from Bacillus sp. JER02

Bacillus sp. JER02 is a bacterial strain that can be grown in a medium containing organic solvents and produce a protease enzyme. JER02 protease was purified with a yield of 31.9% of total protein and 328.83-fold purification. Km and Vmax of this protease were established as 0.826 µM and 7.18 µmol/min, respectively. JER02 protease stability was stimulated about 80% by cyclohexane. It exhibited optimum temperature activity at 70°C. Furthermore, this enzyme was active in a wide range of pH (4-12) and showed maximum activity at pH 9.0. The nonionic detergents Tween-20 and Triton X-100 improved the protease activity by 30 and 20%, respectively. In addition, this enzyme was shown to be very stable in the presence of strong anionic surfactants and oxidizing agents, since it retained 77%, 93%, and 98% of its initial activity, after 1 hr of incubation at room temperature with sodium dodecyl sulfate (SDS), sodium perborate (1%, v/v) and H2O2 (1%, v/v), respectively. Overall, the unique properties of the Bacillus sp. JER02 protease suggested that this thermo- and detergent-stable, solvent-tolerant protease has great potential for industrial applications.

Characterization of solvent stable extracellular protease from Bacillus koreensis (BK-P21A)

A total of 18 protease producing bacterial strains were isolated from detergent effluent in South Korea using skim milk agar medium. A strain (BK-P21A) was selected and identified as Bacillus koreensis based on morphological, biochemical and molecular characterizations (16S rRNA gene sequence analysis). Optimized culture conditions for the production of protease were pH 8.5, 30 °C, sucrose (2%) and yeast extract (0.2%) during 36 h of incubation. Furthermore, the protease was partially purified by ammonium sulphate precipitation (80%) and again by Superdex 200 10/300 GL and Superdex 75 10/300 GL column chromatography, which resulted in 5.0 fold purification and a yield of 23%. The molecular mass of the protease was estimated to be 48 kDa by SDS-PAGE. The purified enzyme was further characterized and found to be most active at pH 9.0 and 60 °C. The activity of the purified protease was enhanced by CaCl₂ and CoCl₂, but inhibited by PMSF, which indicated it was a serine type protease. Moreover, the protease was moderately stable in surfactants and 81% stable in H₂O₂. Finally, the enzyme was more active and stable (94-126.5%) in various hydrophilic organic solvents. Considering the stability of protease towards the alkaline pH, high temperature and organic solvents (50%), the enzyme from B. koreensis can be used as an alternative biocatalyst for several industrial applications mainly for peptide synthesis in nonaqueous solvents.