Please use this identifier to cite or link to this item: http://repository.vnu.edu.vn/handle/VNU_123/10700
Title: Taxonomic study of a thermophilic bacterium and optimization of culture conditions for protease production
Authors: Dao Thi Luong
Vi Dai Lam
Tran Thi Le Quyen
Ha Thi Hang
Pham Duc Ngoc
Duong Van Hop
Keywords: Bacillus subtilis;Protease;Taxonomic;Culture conditions;Enzyme properties
Issue Date: 2011-09-09
Publisher: Tạp chí khoa học ĐHQGHN, Khoa học tự nhiên và công nghệ
Series/Report no.: Tạp chí khoa học ĐHQGHN, Khoa học tự nhiên và công nghệ;27(2S)
Abstract: A bacterial strain YS24 produced high level of extracellular protease was isolated from soil sample collected at Yen Son - Tuyen Quang. Based on the colony observation, cell morphology and the analysis of 16S rDNA nucleotide sequence, the strain YS24 was identified as Bacillus subtilis. The highest levels of extracellular protease production and bacterial growth were obtained by using medium V9 (g/l): Glucose-5; peptone-7.5; MgSO4.7H20-5; K2HPO4-5; FeSO4.7H20-0.1. Enzyme production corresponded with bacterial growth and reached a maximal level of 1,390 U/ml when the bacterium was cultured on the orbital shaker under following condition: at speed of 200 rpm, inoculum size of 7% , temperature of 40-45°C, medium pH of 7.0 -8.0 and incubation time in 48 hours. The best carbon source was either glucose or galactose. The best nitrogen source was peptone or meat extract. Protease activity reached the highest level at pH of 8.0 and temperature of 50 °C. The enzyme retained 93, 86 and 76% of its initial activity after treatment at 60 °C, 70 °C and 80 °C for 10 min, respectively. Enzyme activity was completely lost after exposing to temperature above 90°C.
URI: http://repository.vnu.edu.vn/handle/VNU_123/10700
ISSN: 0866-8612
Language: en
Appears in Collections:IMBT - Bài đăng tạp chí / Tham luận HN-HT

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