Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Purification and Partial Characterization of a Detergent and Oxidizing Agent Stable Alkaline Protease from a Newly Isolated Bacillus subtilis VSG-4 of Tropical Soil: Sib Sankar Giri , V. Sukumaran , Shib Sankar Sen , M. Oviya , B. Nazeema Banu , Prasant Kumar Jena; J. Microbiol. 2011;49(3):455-461. Published online June 30, 2011; DOI: https://doi.org/10.1007/s12275-011-0427-4

Abstract: An extracellular detergent tolerant protease producing strain VSG-4 was isolated from tropical soil sample and identified as Bacillus subtilis based on morphological, biochemical characteristics as well as 16S-rRNA gene sequencing. The VSG-4 protease was purified to homogeneity using ammonium sulphate precipitation, dialysis and sephadex G-200 gel permeation chromatography with a 17.4 purification fold. The purified enzyme was active and stable over a broad range of pH (8.0-11.0, optimum at 9.0) and temperature (40°C to 60°C, optimum at 50°C). The thermostability of the enzyme was significantly increased by the addition CaCl2. This enzyme was strongly inhibited by PMSF and DFP, suggesting that it belongs to the serine protease superfamily. The purified VSG-4 alkaline protease showed remarkable stability in anionic (5 mM SDS) and ionic (1% Trion X-100 and 1% Tween 80) detergents. It retained 97±2% and 83.6±1.1% of its initial activity after 1 h preincubation in the presence of 1% H2O2 and 1% sodium perborate, respectively. Furthermore, the purified enzyme showed excellent stability and compatibility with some commercial laundry detergents besides its stain removal capacity. Considering these promising properties, VSG-4 protease may find tremendous application in laundry detergent formulations.

Production, Partial Characterization, and Immobilization in Alginate Beads of an Alkaline Protease from a New Thermophilic Fungus Myceliophthora sp.: Letícia Maria Zanphorlin , Fernanda Dell Antonio Facchini , Filipe Vasconcelos , Rafaella Costa Bonugli-Santos , André Rodrigues , Lara Durães Sette , Eleni Gomes , Gustavo Orlando Bonilla-Rodriguez; J. Microbiol. 2010;48(3):331-336. Published online June 23, 2010; DOI: https://doi.org/10.1007/s12275-010-9269-8

Abstract: Thermophilic fungi produce thermostable enzymes which have a number of applications, mainly in biotechnological processes. In this work, we describe the characterization of a protease produced in solidstate (SSF) and submerged (SmF) fermentations by a newly isolated thermophilic fungus identified as a putative new species in the genus Myceliophthora. Enzyme-production rate was evaluated for both fermentation processes, and in SSF, using a medium composed of a mixture of wheat bran and casein, the proteolytic output was 4.5-fold larger than that obtained in SmF. Additionally, the peak of proteolytic activity was obtained after 3 days for SSF whereas for SmF it was after 4 days. The crude enzyme obtained by both SSF and SmF displayed similar optimum temperature at 50°C, but the optimum pH shifted from 7 (SmF) to 9 (SSF). The alkaline protease produced through solid-state fermentation (SSF), was immobilized on beads of calcium alginate, allowing comparative analyses of free and immobilized proteases to be carried out. It was observed that both optimum temperature and thermal stability of the immobilized enzyme were higher than for the free enzyme. Moreover, the immobilized enzyme showed considerable stability for up to 7 reuses.

Cloning of the gense coding for extracellular proteases from alkalophilic xanthomonas SP. JK311: Kim, Young Hun , Jang, Ji Yeon , Yeeh, Yeehn , Kim, Yong Ho , Kim, Sang Hae; J. Microbiol. 1995;33(4):344-349.

Abstract: The alkalophilic bacterium, Xanthomonas sp. JK311, producing extracellular proteases, was isolated from soil. Xanthomonas sp. JK311 produced five extracellular proteases that are all metalloproteases. Four of them were resistant against 1% SDS. Chromosomal DNA of the Xanthomonas sp. JK311 was digested with BamHI and cloned into PUC19. Among E. coli strain HB101 transformants, a clone secreting the proteases was screened through halo formation on skim-milk agar plate and by Southern blot analysis. It had the recombinant plasmid pXEP-1 containing the 7.5 kb-BamHI DNA fragment and produced three extacellular proteases. Their protease properties corresponded to those of Xanthomonas sp. JK311.

Purification and Characterization of Caseinolytic Extracellular protease from Bacillus amyloliquefaciens S94: Eui-Sun Son , Jong-Il Kim; J. Microbiol. 2002;40(1):26-32.

Abstract: From the culture supernatant of the psychrotrophic strain of Bacillus amyloliquefaciens an extracellular serine protease was purified to apparent homogeneity by successive purification steps using QAE-Sephadex, SP-Sephadex and Sephacryl S-100 column chromatography. The protease is monomeric, with a relative molecular mass of 23,000. It is inhibited by the serine protease inhibitor phenylmethylsulfonyl fluoride, but not by EDTA. The enzyme is most active at pH 9-10, and at 45 C, although it is unstable at 60 C.

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