Biotechnology Bulletin ›› 2021, Vol. 37 ›› Issue (4): 116-126.doi: 10.13560/j.cnki.biotech.bull.1985.2020-0989

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Construction of Mixed Fermentation System of Four PGPR Strains and Evaluation of Its Promoting Effect

ZHOU Jing(), HUANG Wen-mao, QIN Li-jun, HAN Li-zhen()   

  1. College of Life Sciences/Institute of Agro-bioengineering,Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region(Ministry of Education),Collaborative Innovation Center for Mountain Ecology & Agro-Bioengineering(CICMEAB,Guizhou University),Guiyang 550025
  • Received:2020-08-07 Online:2021-04-26 Published:2021-05-13
  • Contact: HAN Li-zhen E-mail:1846794394@qq.com;lzhan1@gzu.edu.cn

Abstract:

This objective of this work is to construct a mixed fermentation system from 4 plant growth-promoting rhizobacteria(PGPR)strains and to inoculate pepper for laying a foundation for the research and development of microbial compound agents. The medium and fermentation conditions of the mixed fermentation system were optimized by single factor experiment,orthogonal experiment and response surface method. And experiment of planting pepper in pot was conducted to evaluate the growth-promoting effect of compound broth. In mixed fermentation system,the optimal carbon source was sucrose,the optimal nitrogen source was yeast extract,and the optimal carbon-nitrogen ratio was 5∶1. The optimal fermentation conditions were as follows,temperature 29.7℃,pH 7.05,inoculation proportion 3.19%,and the medium volume 50 mL/250 mL. Under these culture conditions,the viable bacterial count in the mixed fermentation culture was 2.94×1014CFU/mL,which was about 5.13 times compared with single strain fermentation. The growth and physiological indexes of pepper seedlings were significantly improved after irrigating with the mixed fermentation broth,i.e.,the plant height,root length,fresh weight,and chlorophyll content increased by 8.01%,50.22%,43.66% and 6.94% compared with the single strain fermentation compound. In Conclusion,the compound agents prepared by the mixed fermentation system of 4 PGPR strains may have higher viable microbial counts,and play better growth-promoting effects on pepper,and have obvious application potential in the development of PGPR compound agent.

Key words: mixed fermentation, fermentation optimization, compound agent, growth-promoting effect of pepper