Kittipat Chotchindakun1, Wasu Pathom-Aree1, Kanchana Dumri2, Jetsada Ruangsuriya3,4, Chayakorn Pumas1, Jeeraporn Pekkoh1,5. 1. Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. 2. Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. 3. Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand. 4. Functional Food Research Unit, Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200, Thailand. 5. Environmental Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Abstract
The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) derived from cyanobacteria is an environmentally friendly biodegradable polymer. The low yield of PHBV's production is the main hindrance to its sustainable production, and the manipulation of PHBV production processes could potentially overcome this obstacle. The present research investigated evolutionarily divergent cyanobacteria obtained from local environments of Thailand. Among the strains tested, Cyanosarcina sp. AARL T020, a hot spring cyanobacterium, showed a high rate of PHBV accumulation with a fascinating 3-hydroxyvalerate mole fraction. A two-stage cultivation strategy with sole organic carbon supplementation was successful in maximizing cyanobacterial PHBV production. The use of an optimized medium in the first stage of cultivation provided a 4.9-fold increase in biomass production. Subsequently, the addition of levulinic acid in the second stage of cultivation can induce significant biomass and PHBV production. With this strategy, the final biomass production and PHBV productivity were increased by 6.5 and 73.2 fold, respectively. The GC-MS, FTIR, and NMR analyses confirmed that the obtained PHBV consisted of two subunits of 3-hydroxyvaryrate and 3-hydroxybutyrate. Interestingly, the cyanobacterial PHBV contained a very high 3-hydroxyvalerate mole fraction (94%) exhibiting a low degree of crystallinity and expanding in processability window, which could be applied to polymers for desirable advanced applications.
The n class="Chemical">poly(3-hydroxybutyrate-co-3-hydroxyvalerate)n> (PHBV) derived from cyanobacteria is an environmentally friendly biodegradable polymer. The low yield of PHBV's production is the main hindrance to its sustainable production, and the manipulation of PHBV production processes could potentially overcome this obstacle. The present research investigated evolutionarily divergent cyanobacteria obtained from local environments of Thailand. Among the strains tested, Cyanosarcina sp. AARL T020, a hot spring cyanobacterium, showed a high rate of PHBV accumulation with a fascinating 3-hydroxyvalerate mole fraction. A two-stage cultivation strategy with sole organic carbon supplementation was successful in maximizing cyanobacterial PHBV production. The use of an optimized medium in the first stage of cultivation provided a 4.9-fold increase in biomass production. Subsequently, the addition of levulinic acid in the second stage of cultivation can induce significant biomass and PHBV production. With this strategy, the final biomass production and PHBV productivity were increased by 6.5 and 73.2 fold, respectively. The GC-MS, FTIR, and NMR analyses confirmed that the obtained PHBV consisted of two subunits of 3-hydroxyvaryrate and 3-hydroxybutyrate. Interestingly, the cyanobacterial PHBV contained a very high 3-hydroxyvalerate mole fraction (94%) exhibiting a low degree of crystallinity and expanding in processability window, which could be applied to polymers for desirable advanced applications.
Authors: Donya Kamravamanesh; Tamas Kovacs; Stefan Pflügl; Irina Druzhinina; Paul Kroll; Maximilian Lackner; Christoph Herwig Journal: Bioresour Technol Date: 2018-06-20 Impact factor: 9.642
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