Influence of fermentation temperature and duration on survival and biocontrol efficacy of Pseudomonas fluorescens Pf153 freeze‐dried cells

Abstract

Aim: The aim of this paper was to determine whether the quality of formulated Pseudomonas fluorescens Pf153 can be influenced by changes in fermentation conditions. In this study, the influence of the fermentation temperature on the growth and its consequence on shelf life, viability and biocontrol efficacy of freeze-dried cells of P. fluorescens Pf153 was investigated. Methods and Results: Cells of P. fluorescens Pf153 were grown at 20 and 28°C in flasks and fermenter and harvested in the mid-log and the beginning of the stationary phase. The survival during storage of freeze-dried cells was tested at 25°C. Cells fermented at 20°C survived in storage better than those grown at 28°C, irrespective of the harvesting time. Compared to the untreated control, in in vitro tests Pf153 was in all production temperature/duration combinations significantly effective against all tested Botrytis cinerea strains. But no differences between temperature/duration combinations were found. In bioassay on detached Vicia faba leaves, it was found that young cells, when fermented at 28°C had a significant positive influence on the biocontrol efficacy.Conclusions: These results demonstrate that fermentation parameters have an influence on the performance and quality of a formulated product. Significance and Impact of the Study: Only limited numbers of biocontrol products based on antagonistic pseudomonads are on the market. This can be attributed to the lack of suitable formulated products with high numbers of viable cells and a good shelf life. Currently, only limited information on the influence of the fermentation on subsequent downstreaming process is available. Within this study, we focused on the influence of the two important parameters fermentation temperature and harvest time on survival, shelf life and biocontrol efficacy of P. fluorescens Pf153.

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A Review on Detailed Understanding and Recent Advances of Biocontrol Agent: Pseudomonas fluorescens

“…This study explains that there has great effect on the bio-control efficacy of P. fluorescens Pf153 because of fermentation parameters (Bisutti et al, 2020)…”

Development of a fluid‐bed coating process for soil‐granule‐based formulations of Metarhizium brunneum , Cordyceps fumosorosea or Beauveria bassiana

“…2016; Gotor‐Vila et al . 2017; Bisutti and Stephan 2020). Therefore, it is likely that malt extract has as well a protective effect during the drying process.…”

“…These bacterial contaminations were not further investigated but the results show us an important hint what may occur in an unsterile soil. Sugar components are known to protect microorganisms within a drying process (Stephan and Zimmermann 1998, Stephan et al 2016, Gotor-Vila et al 2017, Bisutti and Stephan 2020. Therefore, it is likely, that malt extract has as well a protective effect during the drying process.…”