Author(s): Wang SL, Wang CY, Huang TY
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Abstract A protease-producing bacterium, strain TKU012, was isolated from infant vomited milk and identified as Lactobacillus paracasei subsp paracasei. Strain TKU012 produced protease when it was grown in a medium containing squid pen powder of marine waste. An extracellular protease was purified from culture supernatant by DEAE-Sepharose and Sephacryl S-100 chromatography. A protease, purified 77-fold to homogeneity in an overall yield of 11\%, has a molecular weight of about 49 kDa estimated by SDS-PAGE. The protease was maximally active at pH 10 and 60 degrees C and showed substrate specificity to casein and gelatin. The protease retains 21\% and 91\% activity in the presence of Tween 20 (2\% w/v) and SDS (2mM), respectively. The enzyme activity was reduced in the presence of PMSF and showed 23\% sequence coverage rate with metalloprotease of Serratia marcescens. This is the first report of extracellular proteases purified from lactobacilli.
This article was published in Bioresour Technol
and referenced in Journal of Probiotics & Health