Cytochrome P450 BM-3 from Bacillus megaterium was engineered using a combination of directed evolution and site-directed mutagenesis to hydroxylate linear alkanes regio- and enantioselectively using atmospheric dioxygen as an oxidant. Mutant 9-10A-A328V hydroxylates octane primarily at the 2-position to form S-2-octanol (40% ee). Another mutant, 1-12G, hydroxylates alkanes larger than hexane primarily at the 2-position, but forms R-2-alcohols (40-55% ee). These biocatalysts are highly active for alkane substrates and support thousands of product turnovers. These regio- and enantio-selectivities are retained in whole-cell biotransformations with E. coli, where the engineered P450s can be expressed at high levels and the expensive cofactor is supplied endogenously.