Isolation and identification of acid-producing bacteria from environmental samples is still one of important and effective approaches to obtain strains producing lactic acid with high optical purity.In this study,an isolate strain named HL64-1,producing D-lactic acid with high optical purity,was isolated from rotten fruit.And HL64-1 was characterized as Leuconostoc pseudomesenteroides based on morphology,16S rDNA sequence analysis and sequence similarity Blast analysis.After fermentation for 24 h,62.18 g/L D-lactic acid was produced with an optical purity of 99.90％(ee)in basic fermentation culture.The acid production rate was 2.59 g/(L·h).Scale-up fermentation of L.pseudomesenteroides HL64-1 in 5-L fermenter for 72 h produced 78.74 g/L D-lactic acid by replenishment of carbon sources,and the average acid production rate was 1.09 g/(L·h).Moreover,L.pseudomesenteroides HL64-1 was found to be capable of using effectively cheap raw materials,such as agricultural by-products peanut cake meal and cottonseed meal,as alternative nitrogen sources,leading a reduction of fermentation cost.In addition,L.pseudomesenteroides HL64-1 could metabolize xylose into D-lactic acid.Co-fermentation of glucose and xylose mixtures showed that glucose significantly enhanced the utilization efficiency of xylose,making L.pseudomesenteroides HL64-1 to be a promising strain for pure D-lactic acid industrial production.
维普
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