Bioconversion of renewable resources into lactic acid: an industrial view

Abstract

Lactic acid, an anaerobic product of glycolysis, can be theoretically produced by synthetic route; however, it is commercially produced by homo-fermentative batch mode of operations. Factors affecting its production and strategies improving it are considered while devising an optimized protocol. Although a hetero-fermentative mode of production exists, it is rarely used for commercial production. Attempts to use Rhizopus sp. for lactic acid production through either hetero-fermentative or thermophilic conditions were not economical. Since almost 70% of the cost of its production is accounted by raw materials, R & D efforts are still focused to find economically attractive agri-products to serve as sources of carbon and complex nitrogen inputs to meet fastidious nutrient needs for microbial growth and lactic acid production. Therefore, need exists for using multi-pronged strategies for higher productivity. Its present production and consumption scenario is examined. Its optically active isomers and chemical structure permit its use for the production of several industrially important chemicals, health products (probiotics), food preservatives, and bio-plastics. In addition, its salts and esters appear to have a variety of applications.

The effects of nutrient supplements on the production of lactic acid from cheese whey

“…Nutrient supplements such as yeast extract, corn steep liquor and lactamine AA can improve the nutritional quality of the medium, because they contain, all essential amino acids growth promoting compounds, in addition to organic nitrogen, and carbonaceous compounds. However, it is very expensive to use these nutrient supplements in large quantities and can reach as high as 32% of the total lactic acid production cost [18,19]. It has been reported by Senthuran et al [20] and Fitzpatrick et al [21] that the supplementation of whey hydrolysate with yeast extract (YE) and manganese ions was necessary to improve lactic acid production and lactose utilisation.…”

Enantioselective lactic acid production by an Enterococcus faecium strain showing potential in agro-industrial waste bioconversion: Physiological and proteomic studies

“…This has led to a growing demand of lactic acid (LA), the monomeric unit, resulting in a rapid increase of its production, that was about 150000 metric tons per year in 2003 (Hester, 2000a;Bizzarri and Kishi 2003) and has been estimated to grow yearly at 5-8% (Yadav et al, 2011). The annual world market demand for LA was expected to reach 259,000 metric tons by the year 2012 (Martinez et al, 2013), and is forecasted to reach 367,300 metric tons by the year 2017.…”

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“…The initial pH of the fermentation medium considered a critical factor for microbial growth and the selection of LA producing bacteria based on initial pH considers useful parameter in biotechnology [22]. (Table 2).…”