Kan chai nam thing sapparot khemkhon liang chua Rhodopseudomonas spp. phua pen laeng ahan protein rongkhawatthu lae vitamin B12.

Cultivation of R. sphaeroides S in the optimized waste medium and modified Lascelles medium under aerobic-dark condition revealed that growth, photopigments and vitamin B12 contents of the cells cultivated in the optimized waste medium were much higher than those of the cells grown on the modified Lascelles medium. Selection of appropriate strains with high growth rate, photopigments and vitamin B12 content using the optimized pineapple waste medium concluded that, among one hundred and forty eight isolates, the isolate P47 identified as R. sphaeroides was comparable to the other isolates and was selected. Cultivation of the selected strain in the optimized waste medium under aerobic-dark condition yielded the maximum biomass of 3.73 g/l, vitamin B12 content of 72.72 ug/g dry weight after 28-hour cultivation, the maximum bacteriochlorophyll and carotenoid contents were 22.36 and 3.45 mg/g dry weight after 15-hour cultivation respectively, whereas the reference bacterium, R. sphaeroides S, cultivated in the same medium gave only 3.45 g/l of biomass after 28-hour cultivation and vitamin B12 content of 63.33 ug/g dry weight after 24-hour cultivation, the maxium bacteriochlorophyll and carotenoid contents were 18.2 and 2.43 mg/g dry weight respectively after 15-hour cultivation. Cultivation of R. sphaeroides P47 in the optimized waste medium under anaerobic-light conditions yielded the maximum biomass of 2.4 g/l after 96-hour cultivation, vitamin B12 content of 45.65 ug/g dry weight after 48-hour cultivation, the maximum bacteriochlorophyll and carotenoid contents were 27.59 and 3.952 mg/g dry weight respectively after 24-hour cultivation. Cultivation of R. sphaeroides P47 in the optimized waste medium under aerobic-dark and anaerobic-light conditions could reduce the COD contents of 46.74 and 41.59% respectively.