Related Experiment Video
Updated: May 26, 2025

Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass
Published on: June 24, 2016
Production and characterization of copolymers consisting of 3-hydroxybutyrate and increased 3-hydroxyvalerate by
Huan Wang1, Yunyun Ouyang2, Weinan Yang3
1School of Life Sciences, Tsinghua University, Beijing, 100084, China; State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, 810000, China.
Abstract:
Polyhydroxyalkanoates (PHA) with high 3-hydroxyvalerate (3HV) monomer ratios lead to their accelerated biodegradation and improved thermal and mechanical properties. In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with a broad range of 3HV ratios were produced and characterized using the next generation industrial biotechnology (NGIB) chassis Halomonas bluephagenesis (H. bluephagenesis). Wild type H. bluephagenesis was found to produce P(3HB-co-66.31mol% 3HV) when cultured in the presence of valerate. Deletion on the functional enoyl-CoA hydratase (fadB1) increased to 93.11 mol% 3HV in the PHBV copolymers. Through tuning the glucose and valerate co-feeding, PHBV with controllable 3HV ratios were adjusted to range from 0-to-93.6 mol% in shake-flask studies. Metabolic weakening of the β-oxidation pathway paired with flux limitation to the native 3HB synthesis pathway were used to reach the highest reported 98.3 mol% 3HV by H. bluephagenesis strain G34B grown in shake flasks. H. bluephagenesis strain G34B was grown to 71.42 g/L cell dry weight (CDW) containing 74.12 wt% P(3HB-co-17.97 mol% 3HV) in 7 L fermentors. Mechanical properties of PHBV with 0, 22.81, 42.76, 73.49 and 92.17 mol% 3HV were characterized to find not linearly related to increased 3HV ratios. Engineered H. bluephagenesis has demonstrated as a platform for producing PHBV of various properties.
Related Concept Videos
Hydroboration-Oxidation of Alkenes
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Loss of Carboxy Group as CO2: Decarboxylation of Malonic Acid Derivatives
Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation
The carbonyl center is...
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...

