media selection for poly(hydroxybutyrate) production from methanol by methylobacterium extorquens dsmz 1340

plackett-burman design was used for selection of important media components such as carbon and nitrogen sources and minerals which affect poly(hydroxybutyrate) production and cell growth of methylobacterium extorquens dsmz 1340. among the studied variables, nitrogen and phosphorus sources, mgso4 and most of the trace elements were found to be significant variables for phb production from methanol. at best condition (based on phb concentration), dry cell weight, phb content and phb concentration were 3.81 g/l, 21.23 %, and 0.809 g/l, respectively. it was also found that most of the trace elements and phosphorus sources were influential parameters on the growth of microorganism but the kind of nitrogen source was not. the experimental results showed that deficiencies of nitrogen sources (nh4cl and nh4no3), phosphorus sources (k2hpo4 and na2hpo4) and mgso4 in medium, increased phb accumulation.