Strategies to improve lactic acid fermentation –evaluation of alternatives fermentation strategies

Lactic acid is a compound widely used in food, pharmaceutical, medical and chemical industries. Produced from sugars through fermentation, it has emerged as a potential chemical compound to synthesize renewable and biodegradable plastics and possible precursor of higher cost molecules. Its use on industrial scale is still limited due to the relatively high cost of production, comparing to petrochemical products. In order to the lactic acid produced by fermentation be economically competitive, it is necessary to keep low costs which is linked to upstream and downstream processes. Bearing all this in mind in this work, the performance of the microorganisms Lactobacillus delbrueckii and Bacillus coagulans were evaluated aiming the production of L(+)lactic acid without broth neutralization. This strategy intends to facilitate both production and purification of lactic acid with positive impacts on costs and environment. L.delbrueckii has a range of pH growth of 3.3-6.6 at 35°C. B.coagulans is a microaerophilic and thermophilic microorganism, with optimum pH of 5.5-6.5 holding out until 4.5. Tests were performed in 250 mL Erlenmeyer flasks in a shaker at constant temperature. It was found that production of lactic acid without using a neutralizing agent presents considerable lower yield when compared to the fermentation using it. Thus, it is considered necessary to develop strategies which may improve the final yield of lactic acid without the use of neutralization agent, such as in situ extraction of the product, recycling cells and increasing the rate of bioconversion as potential alternatives to increase process performance.