African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5232

Full Length Research Paper

Medium optimization for production of antifungal active substances from antagonistic Brevibacillus laterosporus and its antifungal activity analysis

Zhen Song1, 2, Hui Guo1, 2, Weidong Fu1, Guoliang Zhang1, Hongxia Jiang2, Peng Liu2, Baoqiang Zhou2, Zhengzong Bao2 and Xunli Liu2*
1Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China. 2College of Forestry, Shandong Agricultural University, Taian, China.
Email: [email protected]

  •  Accepted: 26 April 2013
  •  Published: 07 May 2013

Abstract

The antagonist bacterium Brevibacillus laterosporus ZQ2 with broad-spectrum antifungal activity was isolated from an apple rhizosphere at Mount Tai in China. The fermentation medium for the production of antifungal substances from ZQ2 was statistically optimized. In one-factor-at-a-time experiments, five components, including carbon sources, nitrogen sources, and inorganic salt, were selected. Two factors were determined as critical based on the Plackett-Burman design. Steepest ascent experiments were then used to determine the design space containing the optimum point, followed by application of the response surface methodology. A quadratic model fitting the actual production was established using a central composite design. The obtained optimum medium for the antifungal substances production consisted of the following (in g/L): glucose, 15.6; soybean meal, 8.2; starch, 20; ammonium sulfate, 2; and monopotassium phosphate, 1. Furthermore, the inhibition rate of the substances against Rhizoctonia solani increased by more than 132% compared with the control. B. laterosporus ZQ2 strongly inhibited the growth of many apple phytopathogens in vitro. The inhibition rates against different fungi ranged from 55.26 to 79.02%. As well, the strain significantly reduced the disease damage caused by R. solani in the in vivo tests. Maximum disease protection (46.89%) was recorded when the bacterium applied 3 days before pathogen inoculation.

 

Key words: Brevibacillus laterosporus, antifungal activity, fermentation optimization.