Cellulolytic bacteria living in food can be applied to microbial feed additives to improve fiber digestion in animal feeds. In this study, a cellulase-producing bacteria was isolated from salted clam and treated with physical or chemical agents to enhance their enzyme production. The bacteria was identified as a strain of Bacillus subtilis on the basis of 16S rRNA analysis. Endo-1,4-b-D-glucanase (endoglucanase) was produced by the wild type using 0.4% carboxy-methyl-cellulose as a carbon source with maximal activity (0.04 U/mL) after 24 h incubation. Insoluble cellulose and oat spelt xylan were also used as carbon sources for investigation of exoglucanase and xylanase, however, these enzymes were not found in the culture supernatant. Maximum endoglucanase activity of Bacillus subtilis sp. was measured at 50&deg;C and pH 5, respectively. Then, the strain was subjected to classical mutagenesis (UV-irradiation and chemical treatment) to improve endoglucanase production. A mutant strain, P11 treated with ethyl methyl sulfonate was finally selected. Mutant P11 was sub-cultured and tested for endoglucanase production, which was 0.05 U/mL after 24 h growth. The significant difference of endoglucanase production between wild type and mutant P11 was prolonged to 10th generation. Thus, the mutant strain was found to have enhanced endoglucanase production.

Isolation of endo-1,4-b-D-glucanase producing Bacillus subtilis sp. from fermented foods and enhanced enzyme production by&nbsp;developing the mutant strain

This study was conducted to investigate the effects of dietary supplementation of Endoglucanase producing Bacillus subtilis sp. fermented product (EBFP) on growth performance and meat characteristics in broilers. A total of 480, 1 day old ROSS male broiler chicks were obtained from a local hatchery and randomly allotted to 1 of 4 dietary treatments with 6 replicate pens consisting of 20 chicks. Three additional diets were prepared by mixing 0.1% of commercial cellulase, 0.1%, and 0.2% of EBFP with the control diet and all chicks were fed experimental diets and water ad libitum. Feed intake and body weight (BW) were recorded at 0, 3, and 5 week of the experiment. At the end of the experiment, birds fed a diet containing 0.1% of EBFP had the highest BW compared to birds in other groups (P &lt; 0.01). During 0 to 5 week the experimental period, the dietary addition of 0.1% EBFP significantly increased (P &lt; 0.01) BW gain that was higher than that of birds fed the diet in which only a commercial cellulase was added. No significant difference among treatments was observed in carcass weight, carcass yield, left breast, and thigh meat. These results suggest that dietary addition of cellulolytic probiotics may enhance growth performance compared with the single use of probiotics or enzymes.

Effects of dietary supplementation of endo-1,4-b-D-glucanase producing Bacillus subtilis sp.-fermented products on growth performance in broilers&nbsp;

Isolation of endo-1,4-b-D-glucanase producing Bacillus subtilis sp. from fermented foods and enhanced enzyme production by developing the mutant strain

Effects of dietary supplementation of endo-1,4-b-D-glucanase producing Bacillus subtilis sp.-fermented products on growth performance in broilers