Low Crystallinity of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) Bioproduction by Hot Spring Cyanobacterium Cyanosarcina sp. AARL T020

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.

Fabrication and Characterization of Cinnamaldehyde-Loaded Mesoporous Bioactive Glass Nanoparticles/PHBV-Based Microspheres for Preventing Bacterial Infection and Promoting Bone Tissue Regeneration

“…The bands corresponding to PHBV and MBGN were observed in all samples. The adsorption bands at 977 cm −1 , 1178 cm −1 , and 1270 cm −1 can be assumed to be the anti-symmetric vibration of C–O–C stretching in the PHBV matrix; also, the band at 1748 cm −1 can be referred to the ester carbonyl group (C=O) [ 59 ], while the bands at 458 cm −1 and 819 cm –−1 , which are assigned as Si-O-Si bending and symmetric stretching vibration, respectively, indicate the incorporation of MBGN into the PHBV matrix [ 60 ]. The additional CIN in the ratios of 5%, 10%, and 20% (v/v) into PHBV/MBGN microspheres was observed with the gradient intensity at the band 1666 cm −1 suggested as the carbonyl group (C=O) [ 61 ], along with the bands at 700 cm −1 and 750 cm −1 consisted of CH=CH bending in alkenes and –CH bending in the aromatic ring [ 54 ].…”

One-Step Oxidation of Orange Peel Waste to Carbon Feedstock for Bacterial Production of Polyhydroxybutyrate

“…Depending on the PHB application, lower crystallinity can be advantageous; it imparts good mechanical properties and a better extensibility at break into the PHB which eases processability [ 76 , 77 , 78 ]. Lower crystallinity was also reported in the case of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) production [ 79 ].…”

Development and Characterization of Electrospun Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Biopapers Containing Cerium Oxide Nanoparticles for Active Food Packaging Applications

“…The absorption bands at 977, 891, and 820 cm −1 belonged to the C-C groups [63]. Moreover, the absorbance peaks at 1093 and 1184 cm −1 were ascribed to the stretching vibration of ether (C-O-C) [64][65][66]. The spectra of the PHBV containing CeO2NPs also showed similar characteristic peaks as for pure PHBV, demonstrating that the incorporation of CeO2NPs + CTAB did not affect the PHBV spectra.…”