토양으로부터 Poly(3-hydroxybutyrate) [PHB] 합성 균주의 분리 및 저가의 탄소원을 이용한 PHB의 합성
Isolation of Poly(3-hydroxybutyrate) [PHB] Accumulating Bacteria from Soil and Production of PHB from Inexpensive Carbon Substrates
Five bacterial strains were isolated from soil samples and examined for their ability to produce Poly(3-hydroxybutyrate) [PHB] from various carbon sources such as xylose, sucrose, and lactose. These five strains were as Bacillus sp.SS-10, Bacillus sp.SS-16, Bacillus sp.SS-18, Bacillus sp.SS-19, and Corynebacterium sp.SS-15 based on the morphological, cultural, and biochemical characteristics. The optimal temperature, pH, carbon source, and nitrogen source were determined for each strain. For the efficient production of PHB, two step cultivations were carried out. However nutrient limitation did not increase PHB accumulation, and all these strains accumulated PHB during growth. Low concentration of carbon, nitrogen, or phosphate resulted in decreased cell growth and PHB accumulation. High concentration of trace elements in the medium inhibited cell growth and PHB accumulation. These strains accumulated PHB up to 20-50% of dry cell weight from potentially cheap carbon sources. Especially, Bacillus sp.SS-19 and Corynebacterium sp.SS-15 accumulated PHB up to 50% and 40%, respectively from xylose.