Characterization of Bacillus megaterium and Bacillus mycoides Bacteria as Probiotic Bacteria in Fish and Shrimp Feed

Abstract

This study was aimedto identify probiotic characteristics and to test the cellulolytic ability of Bacillus megaterium and Bacillus mycoides bacteria for probiotic microbe candidates in fish and shrimp feed. The description of the cellulolytic and amylolytic abilities of these bacteriawas obtained by non-experimental method and descriptive analysis. Probiotic characteristic identification includes growth curve was obtained through total plate count method, cellular and colony morphology, and cellulase and amylase enzyme activity test using DNS method. Results indicated that the maximum growth of B. megateriumwas observed after six hours at 35.62 x 10 10 (CFU), while B. mycoideswasafter 30 hoursat 42.6 x 10 10(CFU). The macroscopic observation showed that the colony of B. megateriumwas concave and smooth,while B. mycoides was flat, relatively rough, with silken threads around the colony.Both bacteria had milky white color, bacillus shape, Gram positive, and sporous. The activity of cellulose and amylase enzymes in B. megateriumwere 3,974 units/ml and 1,831 units/ml, respectively. The activity of cellulose and amylase enzymes in B. mycoideswere 3,506 units/ml and 3,730 units/ml, respectively. It can be concluded that both bacteria could be proposed as probiotic bacteria in fish feed. Keywords: Characterization, Bacillus megaterium, Bacillus mycoides, probiotic microbes, feed.