This project is to use starch that is present in potato processing waste. Dextrose was produced from the starch and then converted to lactic acid by fermentation process using Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus amylophilus that can produce high lactic acid yield as end product. These bacteria were grown at 30 °C or 37 °C in a rotary shaker at 100 rpm in micro-aerobic conditions. Reducing sugar was assayed by dinitrosalicylic acid method using glucose as the standard. The analysis of lactic acid was carried out using colorimetric method developed by Taylor and using lithium lactate as standards. Lactic acid analysis indicates that all three species ferment starch base substrate (31 g/l and 23 g/l of dextrose equivalent) to lactic acid in 120 hours with 50% conversion efficiency. Lactic acid is recovered, purified and concentrated in the form of sodium lactate and lactic acid is produced by direct fermentation of starch in which ions are transported through ion permeable membrane from the solution to another under the influence of voltage between two end electrodes. Polymerization reaction to synthesize polylactic acid was carried out in oil bath with constant nitrogen gas flow through and/or under vacuum condition. Molecular weights of polylactic acid are in the range of 2,800 and 3,800.