Biosurfactants or microbial surfactants are structurally diverse and contribute to reducing surface and interfacial tension. Apart from being isolated from municipal waste and oil contaminated soil, biosurfactant-producing Bacillus spp. can also be found in fermented foods. Bacillus subtilis produce surfactant, which exhibits antibacterial activity against various pathogenic bacteria. In this study, surfactant-producing Bacillus were isolated from traditional fermented food namely; budu (fish sauce), cincalok (fermented small shrimps), tempeh (fermented soybeans) and tapai ubi kayu (fermented cassava). Identification of surfactin-producing bacteria was conducted using 16S rRNA which indicated that surfactin-producing strains isolated from budu and tempeh are Bacillus subtilis while strains from cincalok and tapai ubi kayu are Bacillus amyloliquefaciens with a sequence similarity of 99%. Characterization of surfactin was carried out by High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LCMS). HLPC analyzes identified major peaks contributing to the presence of surfactin. LCMS analysis detected specific mass to charge ratio (m/z) which contributed to the presence of maximum thirteen surfactin isoforms. Surfactin produced by the isolated strains also exhibited antibacterial activity toward pathogenic bacteria, namely Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Streptococcus pneumoniae, Salmonella Typhimurium, Serratia marcescens and Klebsiella pneumoniae. All isolated strains from the Malaysian fermented food types investigated in this study were able to produce surfactin. In addition, antibacterial screening via agar well diffusion, measurements of MBC and MIC show surfactin produced by the isolated strains have antibacterial activities toward certain Gram-positive and Gram-negative bacteria tested in this study.

A new solvent-producing Clostridium has been isolated from soil used in intensive rice cultivation. The 16S rRNA analysis of the isolate indicates that it is closely related to Clostridium acetobutylicum, with a sequence identity of 96%. The new isolate, named C. acetobutylicum YM1, produces biobutanol from multiple carbon sources, including glucose, fructose, xylose, arabinose, glycerol, lactose, cellobiose, mannitol, maltose, galactose, sucrose and mannose. This isolate can also utilize polysaccharides such as starch and carboxylmethyl cellulose (CMC) for the production of biobutanol. The ability of isolate YM1 to produce biobutanol from agro-industrial wastes was also evaluated for rice bran, de-oiled rice bran, palm oil mill effluent and palm kernel cake. The highest concentration of biobutanol (7.27 g/L) was obtained from the fermentation medium containing 2% (w/v) fructose, with a total acetone-butanol-ethanol (ABE) concentration of 10.23 g/L. The ability of isolate YM1 to produce biobutanol from various carbon sources and agro-wastes indicates the promise of the use of this isolate for the production of biobutanol, a renewable energy resource, from readily available renewable feedstocks. 2015 Elsevier Ltd.