We investigated L-lactic acid production in static batch fermentation of kitchen refuse using a bacterial consortium from marine-animal-resource (MAR) composts at temperatures ranging from 30 to 65 degrees C. At relatively low temperatures butyric acid accumulated, whereas at higher temperatures L-lactic acid was produced. In particular, fermentation at 50 degrees C produced 34.5 g L-1 L-lactic acid with 90% lactic acid selectivity and 100% optical purity. Denaturing gradient gel electrophoresis indicated that dominant bacteria present in the original MAR composts diminished rapidly and Bacillus coagulans strains became the dominant contributors to L-lactic acid production at 45, 50 and 55 degrees C. This is the first report of the achievement of 100% optical purity of L-lactic acid using a bacterial consortium. (c) 2013 Elsevier Ltd. All rights reserved.