Biotransformation of lipids CH,OH b)C-27 hydroxy-sterol c〓0 c)C-27 aldo-sterol COOH CH3 CH2COOH COOH e)C-24 carboxylic acid d)C-27 carboxylic acid CH,COOH COOH CH,CH,COOH f c-22 carboxylic acid g)C-17 keto-derivative Figure 9.2 Generalised metabolic sequences of sterol side chain degradation by side chain First carbon 27 is hydroxylated and oxidised to a carboxylic acid. The resulting acid is degradaton then cleaved to release propionic and acetic acids and a second propionic acid. The final reaction in this sequence results in the formation of a keto group at C-17.Biotransformation of lipids 301 Figure 9.2 Generalised metabolic sequences of sterol side chain degradation by micro-organisms. Fit carbon 27 is hydroxylated and oxidised to a carboxylic acid. The resulting acid is then cleaved to release propionic and acetic acids and a second propionic acid. The final reaction in this sequence results in the formation of a keto pup at C-17. side chain degdaam