Recent advances in microbial production of malic acid from renewable byproducts

In the last few years, ecofriendly malic acid production has received a potential platform for the bio-based chemicals to replace the dependency of fossil based resources. The main goal of this paper is to explore the feasibility of efficient production of malic acid from cost effective alternative renewable byproducts as feedstock. To replace the traditional method of malic acid production from petroleum-based compounds such as maleic acid, the efficiency of fermentation technology for malic acid production using various microorganisms has been improved. To date, glucose is designated as the best substrate for malic acid production. However, few reviews concerning about malic acid production by employing various microbial strains were reported. The current knowledge on the biosynthesis of malic acid has assisted to improve malic acid production using various microbial strains. But, there is still need for the continuous production and replacement of low-cost substrates to increase the yield of malic acid. This review provides an overview about progress, achievements, merits, challenges and future perspectives in malic acid production from cost effective alternative substrates. Thus, malic acid production can be economical using renewable byproducts like crude glycerol by employing appropriate microorganism.