Fermentation of the psyllid-pathogenic fungus Pandora sp. nov. inedit. (Entomophthorales: Entomophthoraceae)

ABSTRACT

Pandora sp. nov. inedit. (ARSEF13372) is a recently isolated entomophthoralean fungus with high potential for psyllid pest control. The use of entomopathogenic fungi as biocontrol agents in large-scale field application requires biomass production in a sufficient quantity and quality. This work is the first attempt to explore the biomass production of the novel entomophthoralean Pandora species in a liquid medium. This study aims at establishing a submerged fermentation process with potential for mass production of the fungus. Three different complex nutrient sources were evaluated for maximising biomass in a liquid shaking culture. Pandora sp. nov. grew best in media containing skimmed milk, but even faster in a mixture of skimmed milk, yeast extract and a low-cost protein hydrolysate from animal by-products. Subsequently, the produced biomass can be encapsulated in biopolymer beads or granules in order to transfer the fungus into an easily applicable form. Therefore, growth as finely dispersed mycelium was promoted by increased media osmolality through the addition of sodium chloride. After the medium had been transferred to a stirred tank bioreactor with a working volume of 8 L, a maximum biomass dry weight of 21 g·L⁻¹ was reached after 48 h. These promising results can pave the way for large-scale fermentation and formulation processes of this novel Pandora species for biological psyllid pest control.

KEYWORDS:

• Entomophthorales
• biological control
• entomopathogenic fungi
• fermentation
• fungal morphology
• stirred tank bioreactor

Author contributions

LCM designed and conducted the experiments in liquid shaking culture, analyzed and visualized the data, conducted statistical analyses, wrote the manuscript and managed the project. MP conducted and analyzed the data of the experiments in the stirred tank bioreactor and wrote manuscript. PH conceptualized the experiments, edited the manuscript and managed the project. JE conceptualized the experiments and edited the manuscript. AVP secured funding and edited the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by funds of the Federal Ministry of Food and Agriculture (BMEL) (Bundesministerium für Ernährung und Landwirtschaft) based on a decision of the Parliament of the Federal Republic of Germany via the Federal Office for Agriculture and Food (BLE) under the innovation support program number 2814900415.