PRODUCTION AND RECOVERY OF POLY-BETA-HYDROXYBUTYRATE FROM WHEY DEGRADATION BY AZOTOBACTER

Three strains of azotobacter chroococcum were studied to produce poly-â hydroxybutyrate as ainclusion body by whey degradation. optimum degradation whey results were obtained when usingwhey broth as a fermentation medium without extra salt, temperature at 35 °c and ph 7 (p<0.05).lambda max for whey broth medium was determined probably about 400 nm. the effect of differentnitrogenous rich compounds (nh4no3, bactopeptone, casein, yeast extract, meat extract, proteasepeptone and tryptone) on whey degradation showed that incorporation of nitrogenous compounds intothe medium did not increase whey degradation by azotobacter chroococcum 1723 (p<0.05). but poly-âhydroxyl-butyrate production was increased in presence meat extract up to 75% of the cell dry weightafter 48h. the addition of nitrogenous sourced (except ammonium nitrate) had a positive effect onpoly-â hydroxyl-butyrate production as it peaked in the presence of meat extract and 4.43 g/l wasaccumulated in comparison to 0.5g at diazotrophically growing cells. increasing the o2 values resultedby shaking at 122 rpm in decreased poly-â hydroxyl-butyrate yield form 4.43 to 0.04 g/l. the resultsshow that this medium supports the growth of strain 1735 and also that this waste could be utilized as acarbon and nitrogen source. production of poly-â hydroxyl-butyrate by using whey as a medium lookspromising, since the use of inexpensive feed-stocks for poly-â hydroxyl-butyrate is essential ifbioplastics are to become competitive products.