Figure 5. Growth and PHB accumulation during cultivation of R. sphaeroides N20 in GA medium with (a) KH₂PO₄; (b) and K₂HPO₄ at various concentrations 0, 0.01, 0.1 and 1 g/l under aerobic-dark condition at 37ºC on shaker (150 rpm) for 60 hrs.