Methanol → (20s)-7alpha-Hydroxy-pregn-4-en-3-one-20-carbaldehyde

Pseudomonas putida D4014-A357-3A strain was inoculated to a slant medium of Medium 1 (as mentioned above) and cultured at 30° C. for one day. Then, 2 loopfuls of the bacterial cells grown were inoculated to a liquid medium (10 ml) of Medium 3 (as mentioned above) containing 3α,7α-dihydroxy-5β-cholanic acid and subjected to shake culture at 30° C. overnight. The obtained culture broth was inoculated to 100 ml of Medium 3 (as mentioned above) having the same composition in a 500 ml Sakaguchi flask and cultured at 30° C., 200 rps for 48 hr. The total amount of 3α,7α-dihydroxy-5β-cholanic acid subjected to the culture was 1.1 g (2.8 mmol). The obtained culture broth was centrifuged at 5000 rpm for 30 min, and water (100 ml) was added to a mixture of the obtained bacterial cells and the product to allow dispersing. The mixture was again subjected to centrifugation to wash the mixture. Methanol (200 ml) was added to the mixture to dissolve the product, and the mixture was filtered to give a clear methanol solution. Water (30 ml) was added to the methanol solution and methanol was partly evaporated in a rotary evaporator. Then, the resulting concentrate was cooled, and the precipitated solid was collected by filtration and dried to give (20S)-7α-hydroxy-pregn-4-en-3-one-20-carbaldehyde (310 mg, 0.90 mmol, yield 32%) having the following property.