A circular bioeconomy concept: Enhanced bioconversion of crude glycerol into 1,3-PDO production by immobilized Clostridium butyricum JKT 37

• Published in: CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY
• Main Authors: Tey, Ker Yee; He, Ning; Luthfi, Abdullah Amru Indera; Woon, Kok Sin; Lee, Chew Tin; Manaf, Shareena Fairuz Abdul; Yeap, Swee Keong; Mahmod, Safa Senan; Silvamany, Hemavathi; Tan, Jian Ping
• Format: Article; Early Access
• Language: English
• Published: SPRINGER 2024
• Subjects: Science & Technology - Other Topics; Engineering; Environmental Sciences & Ecology
• Online Access: https://www-webofscience-com.uitm.idm.oclc.org/wos/woscc/full-record/WOS:001336750700003

Aligning with Sustainable Development Goal 12, National Biomass Action Plan 2023-2030 and the transition of carbon-emission-intensive development to low-carbon solutions, this research proposes a circular bioeconomy concept that utilizes byproduct of the biodiesel industry to create high-value 1,3-propanediol (1,3-PDO). There are limited studies on the bioconversion of biodiesel-derived glycerol into 1,3-PDO via the immobilized cell biocatalysis route. In this study, the production of 1,3-PDO was enhanced by the wild-type Clostridium butyricum JKT 37 immobilized on the coconut shell activated carbon (CSAC) as supporting material using the acidic-pretreated glycerol as a carbon source. Among various mesh sizes of CSAC tested, 6-12 mesh immobilization material had enhanced cell density by about 94.43% compared to the suspended cell system. The immobilized cell fermentation using pretreated glycerol produced 8.04 +/- 0.34 g/L 1,3-PDO with 0.62 +/- 0.02 mol/mol of yield, 15.81% and 27.78% higher than the control, respectively. Five repeated batches of immobilized cell fermentation had resulted in the average 1,3-PDO titer, yield, and productivity of 16.40 +/- 0.58 g/L, 0.60 +/- 0.03 mol/mol, and 0.68 +/- 0.02 g/L.h, respectively, with the biochemical equation of C3H8O2+ 0.18NH(3)-> 0.60C3H(8)O(2) + 0.06C(4)H(8)O(2) + 0.04C(2)H(4)O(2) + 0.18C(4)H(7)O(2)N + 0.93H(2)O + 0.16CO(2) The metabolism pathway gradually shifted to a reductive branch when immobilized cells were reused in repeated batch fermentation, proven by the reduction in organic acid formation, increased ratio of 1,3-PDO-to-total organic acids, and experimental stoichiometry. An inclusive investigation on the variations of glycerol source and their impact on the carbonized immobilizer performance was conducted.