Essai de production de l’acide polylactique (PLA) à partir de la mélasse de canne à sucre en vue d’élaborer les emballages bioplastiques

This work involves the development of a bioplastic replacement for non-degradable plastics in packaging. The objective was to produce polylactic acid (PLA) from sugarcane molasses with locally produced Lactobacillus delbrucckii. Polylactic acid is a biosourced and biodegradable polymer, it can be plasticized. The lactic acid bacteria necessary for the synthesis were isolated and identified as Lactobacillus delbrucckii following their characteristics. The sugar cane molasses used came from the KwiluNgongo sugar mill with a concentration of 410.9 g/L of fermentable sugar. 1L of diluted molasses was fermented with the inoculum of Lactobacillus delbrucckii in a ratio of 10/1. This fermentation produced 98 g of lactic acid after purification (63.6%). Lactic acid was polymerized to polylactic acid (92%), via lactide (78.46%), by ring opening. Lactobacillus delbrucckii colonies were characterized by Gram staining, catalase test, morphology, appearance of the colony and mode of fermentation. The Brix degree, pH, density and fermentable sugar level were determined on the molasses. The polymer obtained had a brittle behavior when heated and its mixture with 5% glycerol gelled more weakly than in the presence of 10% glycerol.