• Microbiology and Biotechnology Letters
• /
• v.43 no.4
• /
• pp.307-313
• /
• 2015

Unpolished rice (UR) is considered to be a healthy alternative to white rice when coping with chronic diseases. In the present study, the fermented slurry of unpolished rice (FSUR) was evaluated with respect to its antimicrobial activities and biochemical characteristics, including the quantities of sugar, total soluble sugar, organic acids, free amino acids, pH, and physiological activity. The antimicrobial efficiency of FSUR was assessed using the paper disc-agar diffusion method. FSUR exhibited strong antimicrobial activity against six pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, and Yersinia enterocolitica) and two fermentation strains (Gluconacetobacter intermedius and Lodderomyces elongisporus). The antimicrobial activity of FSUR was higher than the commercial antibiotics, carbenicillin ($50{\mu}g/ml$) and tetracycline ($50{\mu}g/ml$) against S. aureus, E. coli, L. monocytogenes, P. aeruginosa, S. typhimurium, Y. enterocolitica, and L. elongisporus. Also FSUR had a high antioxidant activity. The microorganisms were isolated from FSUR using tryptic soy broth and yeast extract-peptone-dextrose agar media. The isolated microorganisms were characterized using physiological and biochemical analyses as well as by 16S rRNA gene sequencing and phylogenic analysis. 16S rRNA gene sequence analysis showed that the isolated microorganisms had a high similarity to G. intermedius, Lactobacillus casei, Lactobacillus plantarum, and Acetobacter peroxydans.