Determination of the efficacy of fungal bioreactors to remove E. coli from aqueous dairy manure
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2020
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Abstract
Aqueous dairy manure is a widely used biological soil amendment with high possibility of containing pathogens like Salmonella, Escherichia coli, Listeria, campylobacter and other zoonotic pathogens posing a great threat to food safety by contaminating raw agricultural produce. Proper soil amendment handling and application practices play a major role in food safety by averting the contamination of soil, raw agricultural produce and water supplies by dairy fecal pathogens. These practices help to prevent farm workers and livestock from getting sick by enteric bacteria. The objective of this research is to develop cost effective fungal bioreactors with the white rot fungus Pleurotus ostreatus, and to evaluate its ability in removing E. coli TVS 355 from aqueous dairy manure by assessing different support materials. Fungal growth and nutrient changes were monitored to identify fungal mode of action and efficacy in removing bacterial pathogens. ☐ This study evaluated the efficiency of the white rot fungus P. ostreatus grown on woodchips and spent mushroom compost (SMC) respectively. Results from preliminary experiments showed no changes in the bacterial numbers, and we were unable to complete the bacterial analysis for the actual trials due to the COVID – 19 lockdown. Experimental results showed the different fungal treatments did not significantly affect the concentration of the nutrients of the effluent manure. The live fungal treatment was able to keep the Chemical Oxygen Demand (COD) concentration low for the 10-day period in comparison to the other treatments. Quantification of fungal biomass by measuring the ergosterol content showed that the ergosterol concentration increased over time for the live fungal treatment and gradually degraded over time when the fungi was autoclaved. ☐ There is a huge data gap for potential biocontrol in dairy manure and using white rot fungi within manure waste streams to reduce the presence of pathogens has not been investigated to our knowledge. With more research, the fungal bioreactors have the potential to be one of the efficient, low cost and sustainable methods for treating liquid manure for pathogens.