Extraction Of Round Brown Nitrogen-fixing Bacteria G-3 Strain Poly Hydroxy Alkanoic Acids (pha)

Eight methods for the recovery of polyhydroxyalkanoate(PHA) from the Azotobacter chroococcum G-3 were used to optimize extraction and digestion conditions.Various chemical reagents such as chloroform(CHCl3), sodium hypochlorite(NaClO), SDS, EDTA, HC1, NaOH and various methods were examined for their ability to extract PHA and digest non-PHA cellular materials(NPCM).The result showed that (1) the PHA recovery of 78% at the purity of 98.7% was obtained with the mild mix process by CHC13 and the PHA recovery of 89.6% at the purity of 99% was obtained with the severe mix process by CHC13. (2) the purity and recovery of PHA were 93.6%, 91.1% when the cells were treated for 30 min by 40%(V/V) NaClO. (3) the PHA recovery was 91% and the purity was 96.5% when CHC13 and NaCIO were used together. (4) the SDS mix process made the purity and /ecovery of PHA 89.2% and 90%. (5) the PHA recovery of 87.1% at the purity of 97.5% was obtained when the cells were treated by 0.7(w/v)% SDS for 12 min and then by 30% NaCIO for 3 min. (6) the PHA recovery of 89% at the purity of 97.75% was obtained with the mutual mix process by SDS and EDTA. (7) the purity and the recovery of PHA were 95%, 90.3% with the digestion process by HC1. (8) the PHA recovery of 92% at the purity of 96.2% was obtained with the digestion by NaOH. In addition, physical and mechanical properties of PHA was studied. The result certified the recovered PHA product was coincident with the international quality standard in PHA engineering material for high-performance mechanical applications.This paper was also studied primarily on the decolor of PHA. Physical and chemical methods were all used to decolor the organic phase after the recovery by CHC13 from the cells. The result showed that the effect of chemical methods was not more obvious than that of physical methods and acticarbon decolor was a better method for the decolor of PHA.