Waxes are not common in prokaryotes, but the mycobacteria produce waxes,
termed ‘mycoserosates’, based on branched-chain alcohols or phthiocerols. These are C34 or C36
branched-chain compounds with hydroxyl groups in positions 9 and 11, or 11 and 13. These are
esterified with long-chain fatty acids varying in chain length from C18 to C26 and with two to four
methyl branches that may occur at the 2, 4, 6, and 8 positions. The dimycocerosate esters are
major virulence factors of pathogenic mycobacteria including Mycobacterium tuberculosis and M.
leprae.