Biotechnology Bulletin ›› 2024, Vol. 40 ›› Issue (9): 181-189.doi: 10.13560/j.cnki.biotech.bull.1985.2024-0080

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Screening and Identification of a Bacillus licheniformis Strain with High Electro-transfection Efficiency and Elevated Biomass

DU Wei(), LI Zhi-min(), XING Yan-ming, LIU Pu-lin, MIAO Li-hong   

  1. College of Life Science and Technology, Wuhan Polytechnic University, Wuhan 430023
  • Received:2024-01-19 Online:2024-09-26 Published:2024-10-12
  • Contact: LI Zhi-min E-mail:604003648@qq.com;lizhimin1119@163.com

Abstract:

【Objective】Bacillus licheniformis is an important chassis cell for expressing heterologous proteins in the fermentation industry. Screening B. licheniformis strains with easy electro-transfection and high biomass provides strain resources for effectively improving the host modification efficiency and protein expression level. 【Method】Screening of strains with high homology to B. licheniformis from soil was carried out through enrichment, gyrB amplification, and 16S rDNA sequence analysis. The electro-transfection efficiency and biomass of the screened strains were compared and analyzed with the commonly used chassis cell B. licheniformis 2709 in the industry. The screened strains with easy electro-transfection and high biomass were identified morphologically and physiologically and biochemically as well as were subjected to antibiotic susceptibility assay and growth in high temperature and alkaline environment. 【Result】Ten strains with high homology to B. licheniformis were screened. Among them, the strain 1-33 presented the highest electro-transfection efficiency with a maximum value of 6 700 transformants per μg DNA, which was 13.7 times higher than that of B. licheniformis 2709. Cultured in semi-solid soymeal-corn flour medium and SR liquid medium, the maximum biomass of strain 1-33 was found to be 5.2×1010 CFU/mL and 6.8 g/L, respectively, surpassing B. licheniformis 2709 by 1.71 and 1.3-fold. Further morphological and physiological experiments identified strain 1-33 as Bacillus licheniformis, which had sensitivity to various commonly used antibiotics and good alkaline and heat resistance. 【Conclusion】A B. licheniformis strain 1-33 with high electro-transfection efficiency and elevated biomass is screened, thereby foundation for its further development as an efficient host for exogenous protein expression in industrial process is established.

Key words: Bacillus licheniformis, easy electro-transfection, high biomass, screening, identification