Effects of deleting peptidoglycan hydrolase genes on the viable cell counts of <i>Bacillus amyloliquefaciens</i> and the yield of alkaline protease.

Xiaojian XU; Baoyue Zhu; Xinyue LI; Jinfang Zhang; Wenlong Liu; Fuping LU; Yu LI

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Effects of deleting peptidoglycan hydrolase genes on the viable cell counts of Bacillus amyloliquefaciens and the yield of alkaline protease.

Author: Xiaojian XU ¹ ; Baoyue ZHU ¹ ; Xinyue LI ¹ ; Jinfang ZHANG ¹ ; Wenlong LIU ² ; Fuping LU ¹ ; Yu LI ¹
Author Information

1. Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Bioengineering, Tianjin University of Science & Technology, Tianjin 300457, China.
2. Shandong Longkete Enzyme Preparation Co., Ltd, Yishui 276400, Shandong, China.
Publication Type:Journal Article
Keywords: Bacillus amyloliquefaciens; alkaline protease; gene knockout; peptidoglycan hydrolase; viable cell counts
MeSH: Bacillus amyloliquefaciens/genetics*; Bacterial Proteins; Cell Count; Endopeptidases/genetics*; N-Acetylmuramoyl-L-alanine Amidase/genetics*
From: Chinese Journal of Biotechnology 2022;38(4):1506-1517
CountryChina
Language:Chinese
Abstract: In order to explore the effect of peptidoglycan hydrolase on the viable cell counts of Bacillus amyloliquefaciens and the yield of alkaline protease, five peptidoglycan hydrolase genes (lytC, lytD, lytE, lytF and lytG) of B. amyloliquefaciens TCCC111018 were knocked out individually. The viable cell counts of the bacteria and their alkaline protease activities before and after gene deletion were determined. The viable cell counts of the knockout mutants BA ΔlytC and BA ΔlytE achieved 1.67×10⁶ CFU/mL and 1.44×10⁶ CFU/mL respectively after cultivation for 60 h, which were 32.5% and 14.3% higher than that of the control strain BA Δupp. Their alkaline protease activities reached 20 264 U/mL and 17 265 U/mL, respectively, which were 43.1% and 27.3% higher than that of the control strain. The results showed that deleting some of the peptidoglycan hydrolase genes effectively maintained the viable cell counts of bacteria and increased the activity of extracellular enzymes, which may provide a new idea for optimization of the microbial host for production of industrial enzymes.