engleski

Sustainable Production of D-/L-Lactic Acid by Amylolytic Lactic Acid Bacterium

Market for lactic acid and its biopolymers and consequently capacities for their production continue their steady growth since 2006. Versatility of chemical and pharmaceutical applications of (poly)lactic acid substantially support research activities and innovations focused on sustainable production of the acid from biological resources including waste. Submerged and semi-solid state simultaneous saccharification and fermentation of starch to lactic acid by amylolytic lactic acid bacterium were investigated and novel bioprocess was developed. Defined ratios of two stereoisomeric forms, D- and L-lactic acid, were produced in highly efficient direct conversion of starch and starch-containing raw material. Suitable analytical framework for monitoring key values in liquid and semi-solid phase was formed. Limited availability of amino acids in raw materials was identified as one of major parameter which constrained bacterial amylolytic and fermentative activity as well as efficiency of the semi-solid state bioprocess. Implementation of two different types of bioreactors, stirred tank bioreactor and horizontal rotating tubular bioreactor, was tested on the lab-scale and obtained results represent strong basis for efficient upscaling of the bioprocess and development of integrated bioprocess for lactic acid production.

sustainable production; lactic acid; amylolytic lactic acid bacterium

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