Production of polyhydroxybutyrate (PHB) from bacillus cereus by using rice straw as substrate

• Main Author: Nor Syafarah, Zakariya
• Format: Undergraduates Project Papers
• Language: English
• Published: 2010
• Subjects: TP Chemical technology
• Online Access: http://umpir.ump.edu.my/id/eprint/3429/1/CD5959_NOR_SYAFARAH_BITI_ZAKARIYA.pdf; http://umpir.ump.edu.my/id/eprint/3429/

In this paper, there were 2 main objectives. Those were to To determine the potential of delignification rice straw by using B.cereus and to study the PHB production from B.cereus by using rice straw as substrate. Delignification was crutial due to its chemical durability makes it indigestible to organisms because of its bonding to cellulose and protein material. This lignin sheet acts as a barrier towards the outside elements (Carraher, 2008). The method used for delignification process was fermentation of B.cereus with 250 mL distilled water, 0.5 g yeast extract, 2.5 g peptone, 0.25 g MgSO4.7H 0 and 10 g of rice straw in a 500 mL shake flask. Then, the bacteria were fermented in the medium at 30 ºC and 250 rpm. For the analysis of delignification of rice straw by B.cereus, Klason’s method was utilized. From the result obtained, the highest lignin content was 4.56 % and the Control was 8.18 %. The percentage of the highest lignin degradation for the three samples was 98 %. The average lignin degradation was 78.67 %. After delignification, the bacteria could reacted on the cellulose content to synthesis PHB. The bacteria was fermented in 250 mL distilled water, 0.5 g yeast extract, 2.5 g peptone, 0.25 g MgSO24.7H0 and 1 g of delignified rice straw in a 500 mL shake flask. Then, the bacteria was fermented in the medium at 30 ºC and 250 rpm. The method of analysis of PHB yield was by using UV-vi spectrophotometer at 238nm. From the results obtained, the highest PHB yield is produced in Medium B; the medium consisted of MgSO24.7HO and yeast that yield 2.62 %. By these results, the objectives were achieved.