Canned pineapple syrup, a food processing waste, was utilized as a substrate for lactic acid production by Lactococcus lactis. To improve the utilization of sucrose from the syrup, grape invertase from grape juice derived from wine production was used for sucrose hydrolysis. The highest lactic acid concentrations achieved were 20 and 92 g l(-1) from 20 and 100 g total sugars l(-1), respectively, without a lag period for sucrose consumption.