LACTOSE UTILIZATION POTENTIALS OF FUNGI ISOLATED FROM FERMENTED COW MILK IN BIDA, NIGER STATE, NIGERIA

Abstract

The primary carbohydrate in milk is lactose, which has an anhydrous concentration of about 4.6%. The ability of microorganisms especially fungi to utilize lactose as carbon and energy source is as a result of the production of beta-galactosidase. The use of this enzyme particularly from microbial sources as a biotechnological tool is continuously gaining interests in food, pharmaceutical, medical and other related industries. An attempt was therefore made to isolate and screen fungi from fermented cow milk for potentials to utilize lactose and possible production of beta-galactosidase. Using standard mycological techniques, fungi present in fermented cow milk were isolated, enumerated and characterized. The fungal isolates were further screened for lactose utilization using modified Czapek Dox agar method. The study revealed a low fungal count in the fermented milk samples ranging from 5±0.41cfu/ml to 13.0±0.83cfu/mL. Fungi isolated and identified from the fermented cow milk include Candida kefyr (37%), Candida guillermondii (24%), Saccharomyces cereviae (13%), Aspergillus niger (13%) and Sporothrix schenkii (13%). All the isolates had potentials for lactose utilization with Candida kefyr FPBA01 having the highest potential (20.00 ± 0.00 mm) while the least potential was observed in Candida kefyr (FPBD01) (3.00±2.83 mm). Fermented cow milk is a fairly good source of prospective industrial fungi. The fungi can be exploited for large scale lactose utilization with possible production of beta-galactosidase. These organisms can as well be tested for production of other important bio-products.