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The optimization of fermentation conditions and enzyme properties of Stenotrophomonas maltophilia for protease production
Author(s) -
Wang Zaigui,
Sun Linghong,
Cheng Jia,
Liu Chaoliang,
Tang Xiangfang,
Zhang Hongfu,
Liu Ying
Publication year - 2015
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1361
Subject(s) - proteases , stenotrophomonas maltophilia , protease , bacteria , enzyme , biology , stenotrophomonas , biochemistry , microbiology and biotechnology , fermentation , pseudomonas , genetics , pseudomonas aeruginosa
Intestinal bacteria play a significant physiological role in silkworms. Proteases secreted by intestinal microbes can promote the digestion of the nutrient by Bombyx mori and the absorption of mulberry leaves. Intestinal bacteria from Jingsong × Haoyue in the fourth larvae were isolated and purified to obtain high activity protease‐producing bacteria. The morphology of the identified bacterial colony was examined by microscopy combined with the 16S rDNA method. The results showed that this bacterium was Gram negative and that it belonged to Stenotrophomonas maltophilia , which produces the proteases. To improve the utilization rate of these proteases, we studied the proper culture conditions for producing proteases, and we further studied the properties of the proteases that were produced. The results showed that the optimal enzyme‐producing conditions were as follows: pH of 7.0, culture temperature of 35 °C, incubation time of 36 H, and outfit fluid amount of 60 mL per 100 mL. Meanwhile, the properties of the preliminary enzyme purification indicated that the best pH of the enzymes was 9.0 and the optimal reaction temperature was 50 °C. The enzymes are alkaline proteases that show satisfactory stability at 30 °C and pH 9.0. Consequently, it is suitable for the proteases secreted by S. maltophilia to play a bioactive role in the silkworm gut.