Valorization of barrel washing winery wastewater through production of microbial biocontrol agents

Abstract

Winery wastewater arising from different wine production phases poses a significant environmental threat and economic burden for wine producers considering the legislative requirements regarding the obligatory wastewater treatment. Taking into account the high amount of organic and inorganic nutrients suitable for microbial growth being present in the winery wastewater, the aim of this study was to investigate a possible valorisation route for barrel washing winery wastewater through production of microbial biocontrol agents based on Bacillus sp. The produced biocontrol agents were tested against bacterial and fungal plant pathogens, including Xanthomonas campestris, Xanthomonas euvesicatoria and Aspergillus flavus. The results of in vitro antimicrobial activity testing have shown the high potential of barrel washing winery wastewater to be used as substrate for Bacillus sp. growth, considering that inhibition zone diameters of biocontrol agents based on waste substrate were even higher compared to commercial synthetic medium in case of Aspergillus flavus suppression. This study opens a possibility to further optimize bioprocess conditions including valorisation of barrel washing winery wastewater to maximize antimicrobial activity of the produced biocontrol agents and contribute to the increase of cost-effectiveness of both wine and biocontrol agent?s production.