The microbial oxidation of various primary alcohols to the corresponding aldehydes has been investigated, A focused screening performed amongst some acetic acid bacteria showed that a newly isolated strain of Gluconobacter oxydans oxidizes various short-chain aliphatic alcohols to the corresponding aldehydes with negligible acid production. 3-Methyl-1-butanol (isoamyl alcohol) proved to be the better substrate with high yields (more than 90%) without by-product formation, This biotransformation also occurs with continuous or semicontinuous addition of substrate since the volatile product is removed from the medium under vigorous aeration conditions. Product recovery is attained either by the use of cold traps or by reversible complex formation.