초록
The practicality of using sugarbeet juice as medium to grow Alcaligenes latus (ATCC 29714) for production of polyhydroxybutyrate (PHB), a biodegradable plastic, was explored in this study. Dilute sugarbeet juice, sugarbeet juice with partial and complete addition of nutrients other than sugar were used as culture media. Media with partial nutrient addition was shown to be optimal for PHB production, with final dry cell weight (DCW) 10.30+/-1.01g/L, PHB concentration 4.01+/-0.95g/L, PHB content 38.66+/-7.28%, Y<SUB>p/x</SUB> (gPHB produced per g dry cell weight) 0.39+/-0.07 and a maximum PHB productivity of 0.22+/-0.01g/Lh. The melting temperature of PHB extracted from sugarbeet juice-grown cells supplemented with partial nutrients was measured to be 151.46<SUP>o</SUP>C with crystallinity of 43.12% and the corresponding crystallinity temperature of 45.42<SUP>o</SUP>C. Thermal degradation of extracted PHB occurred from 255.14 to 283.69<SUP>o</SUP>C with the degradation peak at 273.86<SUP>o</SUP>C.