Transforming acid whey into a resource by selective removal of lactic acid and galactose using optimized food-grade microorganisms

Bioresour Technol. 2023 Nov:387:129594. doi: 10.1016/j.biortech.2023.129594. Epub 2023 Aug 1.

Abstract

The presence of lactic acid and galactose makes spray drying of acid whey (AW) a significant challenge for the dairy industry. In this study, a novel approach is explored to remove these compounds, utilizing food-grade microorganisms. For removing lactic acid, Corynebacterium glutamicum was selected, which has an inherent ability to metabolize lactic acid but does so slowly. To accelerate lactic acid metabolism, a mutant strain G6006 was isolated through adaptive laboratory evolution, which metabolized all lactic acid from AW two times faster than its parent strain. To eliminate galactose, a lactose-negative mutant of Lactococcus lactis that cannot produce lactate was generated. This strain was then co-cultured with G6006 to maximize the removal of both lactic acid and galactose. The microbially "filtered" AW could readily be spray dried into a stable lactose powder. This study highlights the potential of utilizing food-grade microorganisms to process AW, which currently constitutes a global challenge.

Keywords: Acid whey; Adaptive laboratory evolution; Corynebacterium glutamicum; Galactose; Lactic acid.

MeSH terms

  • Acids / metabolism
  • Galactose / metabolism
  • Lactic Acid / metabolism
  • Lactococcus lactis* / metabolism
  • Lactose / metabolism
  • Whey Proteins / metabolism
  • Whey* / metabolism

Substances

  • Lactic Acid
  • Galactose
  • Lactose
  • Whey Proteins
  • Acids