Production of lactic acid using a new homofermentative Enterococcus faecalis isolate

Authors

  • Mohan Raj Subramanian,

    1. Center for Bioprocessing Research and Development, South Dakota School of Mines and Technology, Rapid City, SD, USA
    Current affiliation:
    1. Center for Research and Development, PRIST University, Vallam, Thanjavur, TN, India
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  • Suvarna Talluri,

    1. Center for Bioprocessing Research and Development, South Dakota School of Mines and Technology, Rapid City, SD, USA
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  • Lew P. Christopher

    Corresponding author
    1. Center for Bioprocessing Research and Development, South Dakota School of Mines and Technology, Rapid City, SD, USA
    2. Department of Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD, USA
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  • Funding Information Financial support by the Center for Bioprocessing Research & Development (CBRD) at the South Dakota School of Mines & Technology (SDSM&T), the South Dakota Board of Reagents (SD BOR), the South Dakota Governor's Office for Economic Development (SD GOED), and the US Air Force Research Laboratory (AFRL) is gratefully acknowledged.

Summary

Lactic acid is an intermediate-volume specialty chemical for a wide range of food and industrial applications such as pharmaceuticals, cosmetics and chemical syntheses. Although lactic acid production has been well documented, improved production parameters that lead to reduced production costs are always of interest in industrial developments. In this study, we describe the production of lactic acid at high concentration, yield and volumetric productivity utilizing a novel homofermentative, facultative anaerobe Enterococcus faecalis CBRD01. The highest concentration of 182 g lactic acid l−1 was achieved after 38 h of fed-batch fermentation on glucose. The bacterial isolate utilized only 2–13% of carbon for its growth and energy metabolism, while 87–98% of carbon was converted to lactic acid at an overall volumetric productivity of 5 g l−1 h−1. At 13 h of fermentation, the volumetric productivity of lactate production reached 10.3 g l−1 h−1, which is the highest ever reported for microbial production of lactic acid. The lactic acid produced was of high purity as formation of other metabolites was less than 0.1%. The present investigation demonstrates a new opportunity for enhanced production of lactic acid with potential for reduced purification costs.

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