Some Prototheca sp. are known to be involved in n-hexadecane degradation. Two derivatives derived from n-hexadecane in such Prototheca sp. were identified as 5-hexadecanone and 5-hexadecanol. n-Hexadecane was assumed to be converted to 5-hexadecanol and then to 5-hexadecanone through a unique subterminal oxidation pathway in such Prototheca sp.