Industrial Production of Lactic Acid
2011; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-08-088504-9.00177-x
AutoresCurtis Miller, Arlene Fosmer, Brian Rush, Tom McMullin, Daniel R. Beacom, Pirkko Suominen,
Tópico(s)Microbial Metabolic Engineering and Bioproduction
ResumoLactic acid ranks among the high-volume chemicals produced microbially, with an annual world production volume in the range of 370 000 MT. World lactic acid production has expanded 10-fold in the last decade due, in large part, to increased demand for green products derived from lactic acid, including ethyl lactate and polylactic acid (PLA). In order for these products to be competitive in the marketplace, their cost of production must be minimized. Research efforts to improve the economics of lactic acid production have most recently focused on genetic engineering of yeast to produce lactic acid at low pH while at the same time maintaining high rates and yields of production. Many yeasts offer advantages over the traditional bacterial strains, including the ability to grow rapidly on simple defined salt media and the lack of susceptibility to phage infections – features that contribute to a more robust and cost-competitive process. Yeasts also offer the advantage of tolerance to low-pH conditions, which allows the process to avoid costs associated with fermentation neutralization and downstream acidification. Metabolic engineering of yeast has been utilized successfully by several groups to block ethanol formation and replace the metabolic outlet with a lactic acid production pathway. Cargill has taken this approach farthest by engineering and improving lactic acid production in a proprietary yeast all the way to commercially feasible rates, yields, and titers, then developed a process and implemented it at a commercial scale.
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