Abstract: The present invention provides for a method to increase the free lipoic acid production in an isolated genetically engineered bacteria or yeast cell. The method involves culturing in a cysteine supplemented culture medium the engineered bacteria or yeast that is transformed with a recombinant expression vector encoding polynucleotide molecules that results in the overexpression of the following genes that are linked to at least one promoter: (1) substrate protein (e.g. Gcv3p); (2) octanoyltransferase or lipoyl synthase; (3) cofactor S-adenosyl methionine synthase; and (4) lipoamidase. The invention also relates to the engineered bacteria or yeast cell thereof.