| dc.description.abstract | Abstract
Producing the biodegradable material by using mircoorganism system. It is a more important topic to solve the pollution of plastics in the whole world. The environmental pollution is a big problem as a result of the pollution of plastics. For this reason, people start studying biodegradable material. Biodegradable polymers, poly(3-hydroxybutyric) acid (PHB), and a copolymer, poly(3-hydroxybutyric-cohydroxyvaleric) acid [P(HB-co-HV)], are accumulated inside the cells as reserves.
Kineosphaera limosa is a high-G+C Gram-positive, motile, non-spore-forming coccus capable of accumulating significant amounts of polyhydroxyalkanoate (PHA) was isolated from an inefficient biological phosphorus removal activated sludge reactor by Dr. Liu Wen-Tso. The NADH needs reducing power during producing PHAs. And it is good for the bacteria with the few oxygen to producing the NADH. In this study, I researched about different agitation versus producing PHBV and producing different PHB/PHV ratio by using two stages.
In the flask experiments, the test of three different single carbon source：glycerol、glucose and sodium acetate, when the glucose is the only single carbon source, the quantity of PHBV output is more and PHV/PHBV ratio is 85%.
In the fermentation experiments, with different agitation rate, the higher rate will provide more oxygen. The oxygen transfer rate coefficient (kLa) is from 1.91 to 3.68 hr-1，when the agitation rate is from 100 to 200 rpm. With higher agitation rate, the PHB/PHBV ratio is different from 5% to 99%. And lower agitation rate will make the oxygen transfer down, that the specific
growth rate(μ) is decreasing but the PHV/PHBV ratio is increasing.
After the agitation rate 200 rpm for 66 hr, the agitation rate was shifted to the agitation rate 100 rpm In two stage different agitation rate. Because the specific growth rate(μ) is fast during agitation rate 200 rpm, it is difficult to look for the suitable shifted point. With prior experience, I started the agitation rate from 150 rpm to 220 rpm. After the agitation rate 150 rpm for 85 hr, the agitation rate was shifted to the agitation rate 220 rpm. Before shifting ,the PHB/PHBV ratio is 0%. After shifting, the PHB/PHBV ratio is decreasing from 17% to 13%. It is higher than PHB/PHBV ratio 5~6% during the single agitation rate 100~150rpm. | en_US |