Abstract:
The objective of this work was to use oil palm empty fruit bunch (OPEFB) fiber, a solid waste of palm oil mill as a raw material, for a production of the high value substance, coenzyme Q10. Therefore, the experiments were as follows: (1) delignin of the fiber with alkali-peroxide; (2) hydrolysis the fibers with acid and (3) using the hydrolysate products for coenzyme Q10 production by the wild type (Rhodobacter sphaeroides S10) and its mutant strains. Various concentrations of hydrogen peroxide did not affect delignification of the fibers with same particle size, but it affected toward the fibers with differ in particle sizes significantly (p <0.05). Lignin of the fibers with sizes of <0.85 and 0.85-4.75 mm were 29.38 and 24.78% removed, respectively. The delignified fiber was acid hydrolysis better (38.43%) than that of the undelignified fiber (30.45%). Xylose contents of the hydrolysate products of the delignified fiber higher than the undelignified fiber.
The bacterial strains were cultivated for 96 h for the maximum coenzyme Q10 production by using 30 mM mixed carbons of the hydrolyzate as a substrate. Under aerobic-dark conditions, the wild-type strain and the mutant strains, S10-5M, S10-5M-A, S10-5M-B and S10-5M-C, produced 1.86, 1.98, 1.71, 1.70 and 1.79 mgCoQ10/gDCW, respectively. While under anaerobic-light conditions, coenzyme Q10 of all strains was decreased (1.34, 1.36, 1.38, 1.41 and 1.42 mgCoQ10/gDCW, respectively). Pigment contents of the wild-type and the mutant strains, S10-5M, S10-5M-A, S10-5M-B and S10-5M-C, under aerobic-dark conditions were 12.90, 11.10, 9.97, 11.46 and 9.11 mg/gDCW, whereas under anaerobic-light conditions were 12.09, 14.50, 14.97, 10.04 and 10.01 mg/gDCW, respectively. Therefore, the aerobic-dark was a suitable condition for coenzyme Q10 production than anaerobic-light condition. Under anaerobic-light conditions, coenzyme Q10 content of the mutant strains higher than that of the wild type strain. Production of coenzyme Q10 was inversely correlated with the production of pigment.
Hydrogen peroxide was added after aerobic-dark fermentation took place for 48 h, and coenzyme Q10 contents were examined at 96 h. The wild type and the mutant strains, S10-5M, S10-5M-A, S10-5M-B and S10-5M-C, produced 1.75, 1.82, 1.65, 1.60 and 1.67 mgCoQ10/gDCW, respectively. In the case of nicotine addition, the bacteria produced 1.76, 1.76, 1.72, 1.58 and 1.66 mgCoQ10/gDCW, respectively. Additions of hydrogen peroxide and nicotine did not enhance coenzyme Q10 contents but they increased pigment contents.
WALAILAK UNIVERSITY. CENTER FOR LIBRARY RESOURCES AND EDUCATIONAL MEDIA