Fermentative Synthesis of Lactic Acid
Published: 2017
Author(s) Name: Shweta Kashid, Tejashree Dhamale, Srushti Deshpande |
Author(s) Affiliation: Department of Biotechnology, Sinhgad College of Engineering, Pune, Maharashtra, India.
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Abstract
Lactic acid, an organic acid is a product of glucose fermentation in certain cells of organisms. Lactic acid is a crucial metabolite that has gained immense industrial importance. Lactic acid application have a wide expanse including its use to synthesize various fermentation products in food industry, pharmaceutical solutions for drug delivery, preservative in foodstuffs, production of surfactants used in soaps and detergents, tanning leather, synthesis of bio composites and as a mordant in textile industries. Due to its wide applications, it is necessary to study and optimize fermentative synthesis of lactic acid. Lactic acid bacteria were isolated from sources of sauerkraut and cheese water. Sauerkraut is a fermentation product that has a number of lactic acid bacteria thriving on it including, Lactobacillus plantarum, Leuconostoc argentinum, Lactobacillus brevis, Pediococcus pentosaceus. Cheese being a major source of lactic acid bacteria such as Lactobacillus helveticus, Lb. delbrueckii subsp. bulgaricus, Lactococcus lactis, Lb. casei was investigated as a source for the synthesis of lactic acid. Fermentation parameters were optimized and fermentation was carried out for a period of 5 days. Extraction method was followed to separate and purify lactic acid produced. CaCO3 precipitation was carried out to separate lactate from other impurities, followed by acidification with concentrated sulphuric acid. This method showed lesser concentration of lactic acid, so it was further optimized to concentrate the product. In the second method, the concentration of sulphuric acid was lowered (63%) as it outweighed the product and the main impurity water was removed by distillation. CaCO3 precipitation, followed by acidification and distillation is an inexpensive technique in comparison to other techniques. The yield of lactic acid produced was checked by using buttermilk powder as a standard and it was found to be 42.78% and 61% respectively for sauerkraut and cheese mixed cultures.
Keywords: Bioplastics, Lactic acid, Polylactic acid.
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