Danish enzymes producer Novozymes is a very busy company these days both in the areas of renewable chemicals and biofuels.
I tried to find more information on malic acid as this chemical building block is unfamiliar to me. According to Novozymes, malic acid belongs to the group of C4 dicarboxylic acids along with succinic acid and fumaric acid.
According to a 2004 biomass chemicals report by the US Department of Energy (DOE) --which you can download at the blog's green files-- secondary chemicals that can come out of malic acid include hydroxybutyrolactone and hydroxy succinate derivatives.
Malic acid is currently produced from fumaric acid or maleic acid, both derived from maleic anhydride, which in turn is produced from vapor-phased oxidation of hydrocarbons particularly butane. According to the DOE report, the conversion from fumaric to malic is done using fermentation.
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