An isolated Streptococcus sp. strain converted food waste efficiently into lactic acid. Max. productivity was 2.16 g L−1 h−1 and yield was 0.81 g g−1 of available sugars. Increase in solid-to-liquid ratio resulted in increased lactic acid titer. A solid-to-liquid ratio of 20% (w/w) gave 58 g L−1 lactic acid. Downstream processing resulted in a 702 g L−1 optical pure L(+)-lactic acid solution.