ISOLATION OF ANAEROBES IN DIGESTATE OBTAINED FROM CATTLE REMEN, FOOD WASTE AND FRUIT WASTE

ABSTRACT

Anaerobic digestate is the resultant material following anaerobic digestion of biodegradable materials. Despite its high nutrient composition, their safety measured by the concentration of pathogens present is of great concern to its users. Hence this study seeks to add to knowledge on the presence of anaerobic bacteria which are viable but non-culturable in digestate. A total of 30 digestate samples were obtained in a sterile universal sample bottle and transported immediately to the laboratory where standard microbiological technique was used to enumerate, isolate and identify anaerobes. Results of this study showed that anaerobic bacteria count ranges from 1.94±0.2963Log10cfu/g to 3.20±0.9061 Log10cfu/g Statistically the anaerobic bacteria count differ significantly with respect to component of waste before digestion. Clostridium and Fusobacterium species were the anaerobic bacteria flora present. Antibiotics susceptibility pattern of bacteria isolates showed revealed that two species of Clostridium isolated were resistant to Vancomycin and one was resistant to Gentamycin. Fusobacterium sp. isolated in this study showed no resistance to antibiotics. These isolates had a multidrug resistance index below 0.2 hence, possess no threat to public health. The presence of these two genera of bacteria in anaerobic digestate which are regarded as viable but non-cultural (VBNC) should send a message. Hence, proper analysis of these digestate should be carried out before application as manure on farmlands so as to prevent the spread of a deadly microorganism which might be difficult to isolate.