Characterization of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) biosynthesized by mixed microbial consortia fed fermented dairy manure

Abstract

The bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), was isolated from a bioreactor using mixed microbial consortia fed volatile fatty acids (VFA), from fermented dairy manure, as the carbon source. The molar fraction of 3-hydroxyvalerate (3HV) amounted to 0.33 mol mol 21 for two isolated PHBV samples as determined by GC-MS and 1 H-NMR spectroscopy. The chemical, thermal, and mechanical properties were determined. The PHBVs had relatively high M w (790,000 g mol 21 ). Only a single glass transition temperature (T g ) and melting point (T m ) were observed. Isolated PHBVs exhibited good flexibility and elongation to break as compared with commercial PHBVs with lower HV. The diad and triad sequence distributions of the monomeric units were determined by 13 C-NMR spectroscopy and followed Bernoullian statistics suggesting that the PHBVs were random. The PHBV sequence distribution was also characterized by electrospray ionization-mass spectrometry (ESI-MS n ) after partial alkaline hydrolysis to oligomers showing a random 3HV distribution.

Production and characterization of bio-oil and biochar from the pyrolysis of residual bacterial biomass from a polyhydroxyalkanoate production process

“…Biomass used in this study was collected from a pilot-scale PHA producing bioreactor fed with fermented dairy manure [7]. Briefly, dairy manure was collected from the University of Idaho North Farm Dairy and fed to a continuously operated 800 L anaerobic fermenter operated under a 24 h cycle time with solid and hydraulic retention times of 4 days.…”

“…However, the PHA production process from waste streams using MMCs generates relatively lower PHA content as compared with that from pure substrates and pure microbial cultures [3]. In our recent study, PHA (specifically polyhydroxybutyrate-co-hydroxyvalerate, PHBV) was biosynthesized from fermented dairy manure by MMCs [7]. The PHBV content reached up to 40% of the dry cell weight with HV content ranging from 15 to 40 mol%.…”

“…Recently, inexpensive carbon/nitrogen sources such as agricultural residues or industrial waste and woody biomass streams have become competitive carbon sources to reduce the PHA production cost by at least 50% [5][6][7][8]. The use of mixed microbial cultures (MMCs) has been proposed as an ideal alternative to current commercial PHA production (recently reviewed by Laycock et al [9]).…”

Thermophysical properties and biodegradation behavior of green composites made from polyhydroxybutyrate and potato peel waste fermentation residue

“…Some of the most common used bioplastics include thermoplastic starch, cellulose esters and ethers, polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and bio-derived polyethylene (Chen and Patel, 2012;Mekonnen et al, 2013;Wei et al, 2014;Yu et al, 2006). PHAs are a family of biopolyesters that are biosynthesized by microorganisms (Chen and Patel, 2012;Mekonnen et al, 2013).…”

Ultraviolet radiation pre-treatment modifies dairy wastewater, improving its utility as a medium for algal cultivation

“…The CH 4 is used to power a suite of generators for either onsite electricity use or to supply base-load electricity to regional electrical grids [8]. A complementary strategy to AD to further reduce GHG emissions from manure management involves bacterial utilization of manure-based organic carbon (sugars, organic acids, lipids) to synthesize polyesters of hydroxyalkanoates known as polyhydroxyalkanoates (PHAs) -a polyester molecule that can be formed into biodegradable plastics [9][10][11]. PHA is an intracellular carbon and energy storage molecule produced by bacteria during times of excess carbon and/or nutrient deficiency [12].…”