Efficient production of heat-stable antifungal factor through integrating statistical optimization with a two-stage temperature control strategy in Lysobacter enzymogenes OH11

Bao Tang,Huiyong Xu,Cheng Sun,Fengquan Liu,Gaoge Xu,Yancun Zhao

doi:10.1186/s12896-018-0478-2

Abstract

BackgroundHeat-stable antifungal factor (HSAF) is a newly identified broad-spectrum antifungal antibiotic from the biocontrol agent Lysobacter enzymogenes and is regarded as a potential biological pesticide, due to its novel mode of action. However, the production level of HSAF is quite low, and little research has reported on the fermentation process involved, representing huge obstacles for large-scale industrial production.ResultsMedium capacity, culture temperature, and fermentation time were identified as the most significant factors affecting the production of HSAF and employed for further optimization through statistical methods. Based on the analysis of kinetic parameters at different temperatures, a novel two-stage temperature control strategy was developed to improve HSAF production, in which the temperature was increased to 32 °C during the first 12 h and then switched to 26 °C until the end of fermentation. Using this strategy, the maximum HSAF production reached 440.26 ± 16.14 mg L− 1, increased by 9.93% than that of the best results from single-temperature fermentation. Moreover, the fermentation time was shortened from 58 h to 54 h, resulting in the enhancement of HSAF productivity (17.95%) and yield (9.93%).ConclusionsThis study provides a simple and efficient method for producing HSAF that could be feasibly applied to the industrial-scale production of HSAF.

Highlights

Heat-stable antifungal factor (HSAF) is a newly identified broad-spectrum antifungal antibiotic from the biocontrol agent Lysobacter enzymogenes and is regarded as a potential biological pesticide, due to its novel mode of action
Recent advances have started to focus on this issue, and HSAF production by L. enzymogenes OH11 was increased with a screened medium to 356.34 mg L− 1, which is approximately 12-fold higher than that of a conventional medium (10%TSB, 29.34 mg L− 1) [11]
Screening of significant factors affecting HSAF production using Plackett-Burman design (PBD) To evaluate which physical parameters exert a significant effect on the production of HSAF by L. enzymogenes OH11, Plackett-Burman experiments were executed, and the results are presented in Additional file 1: Table S1

Summary

Introduction

Heat-stable antifungal factor (HSAF) is a newly identified broad-spectrum antifungal antibiotic from the biocontrol agent Lysobacter enzymogenes and is regarded as a potential biological pesticide, due to its novel mode of action. The key genes involved in the biosynthesis of HSAF were identified as pks/ nrps in L. enzymogenes C3 [2]. Recent advances have started to focus on this issue, and HSAF production by L. enzymogenes OH11 was increased with a screened medium to 356.34 mg L− 1, which is approximately 12-fold higher than that of a conventional medium (10%TSB, 29.34 mg L− 1) [11]. This production level is still lower than that required for large-scale industrial production, and the effects of fermentation parameters on the production of HSAF have not been studied. It is necessary to investigate fermentation conditions to maximize HSAF production

Methods

Results

Discussion

Conclusion