Abstract
The significance of cellulose in herbivore diets and its digestion by specialized microorganisms in animal digestive systems cannot be overestimated. The efficient cellulose breakdown in ruminants due to cellulolytic microorganisms producing enzymes like cellulases, contrasting with monogastric animals that rely on hindgut fermentation is a rising concern. The study explores the potential use of cellulolytic Bacillus subtilis as probiotics for improved cellulose digestion in monogastric animals. Coventional culture and biochemical identified were employed followed by detection of carboxymethyl cellulase activity, filter paper degradation, pathogenicity testing, fermentation of isolates, stomach acid tolerance testing, and evaluation of probiotics on albino mice fed varying concentrations of Bacillus subtilis. Five isolates of Bacillus subtilis were discovered on CMC agar plates, Clear zones of cellulose hydrolysis were observed on the Carboxymethyl Cellulose agar plates on flooding with Gram’s iodine. A significant difference was observed among the mean clear zones of the isolates [F (5, 12) = 147.81, p < 0.001]. The filter paper degradation result showed that Whatman no.1 filter paper (area 26.80cm2) was completely disintegrated after 96 hours of incubation by the isolate CD1A, and CD6; and partially degraded by isolate CD1C and CD2A. No degradation was observed in Isolate CD3. The total viable counts of the isolates decreased with time with isolate CD1A having the highest mean viable count of 2.72±0.029 x 107 CFU/ml and a percentage viability of 64.15% after 3 hours of incubation. CD3 had the least mean viable count of 0.81±0.031 x 107 CFU/ml and viability of 19.24%. Significant difference was observed between experimental groups treated with Probiotic CD2A (F(3.44)=4.678, p=0.006) and CD6 (F(3,44)=3.982, p=0.014). Only group 3 mice of CD2A and CD6 probiotics were significantly different from the control. There is a need for further investigations into the microbiome of the mice's gastrointestinal tract to quantify the probiotic effects of the Bacillus subtilis isolates.

Key words: Bacillus subtilis, Cellulose, Degradation, Probiotics