The potential of Burkholderia thailandensis E264 for co-valorization of C and C sugars into multiple value-added bio-products.

Despite known metabolic versatility of Burkholderia spp., sugar metabolism and end-product synthesis patterns in Burkholderia thailandensis have been poorly characterized. This work has demonstrated that B.

Biosynthesis and properties of polyhydroxyalkanoates synthesized from mixed C and C sugars obtained from hardwood hydrolysis.

Glucose and xylose are fermentable sugars readily available from lignocellulosic biomass, and are a sustainable carbon substrate supporting industrial biotechnology. Three strains were assessed in this work - Paraburkholderia sacchari, Hydrogenophaga pseudoflava, and Bacillus megaterium - for their ability to uptake both C and C sugars contained in a hardwood hydrolysate produced via a thermomechanical pulping-based process with concomitant production of poly(3-hydroxyalkanoate) (PHA) biopolymers. In batch conditions, B.

The Thermal and Mechanical Properties of Medium Chain-Length Polyhydroxyalkanoates Produced by LS46 on Various Substrates.

Medium chain-length polyhydroxyalkanoates (mcl-PHA) were produced by LS46 cultured with a variety of carbohydrate and fatty acid substrates. The monomer compositions and molecular weights of the polymers varied greatly and was dependent on whether the substrate was metabolized via the fatty acid degradation or the fatty acid synthesis pathways. The highest molecular weights were obtained from medium chain-length fatty acids, whereas low molecular weights were obtained from longer chain-length and more unsaturated fatty acids or carbohydrates.

Rheological Behavior of High Cell Density LS46 Cultures during Production of Medium Chain Length Polyhydroxyalkanoate (PHA) Polymers.

The rheology of high-cell density (HCD) cultures is an important parameter for its impact on mixing and sparging, process scale-up, and downstream unit operations in bioprocess development. In this work, time-dependent rheological properties of HCD LS46 cultures were monitored for microbial polyhydroxyalkanoate (PHA) production. As the cell density of the fed-batch cultivation increased (0 to 25 g·L cell dry mass, CDM), the apparent viscosity increased nearly nine-fold throughout the fed-batch process.

Development of High Cell Density Cultivation Strategies for Improved Medium Chain Length Polyhydroxyalkanoate Productivity Using LS46.

High cell density (HCD) fed-batch cultures are widely perceived as a requisite for high-productivity polyhydroxyalkanoate (PHA) cultivation processes. In this work, a reactive pulse feed strategy (based on real-time CO or dissolved oxygen (DO) measurements as feedback variables) was used to control an oxygen-limited fed-batch process for improved productivity of medium chain length (mcl-) PHAs synthesized by LS46. Despite the onset of oxygen limitation half-way through the process (14 h post inoculation), 28.

Bioreactor Operating Strategies for Improved Polyhydroxyalkanoate (PHA) Productivity.

Microbial polyhydroxyalkanoates (PHAs) are promising biodegradable polymers that may alleviate some of the environmental burden of petroleum-derived polymers. The requirements for carbon substrates and energy for bioreactor operations are major factors contributing to the high production costs and environmental impact of PHAs. Improving the process productivity is an important aspect of cost reduction, which has been attempted using a variety of fed-batch, continuous, and semi-continuous bioreactor systems, with variable results.

The role of dissolved oxygen content as a modulator of microbial polyhydroxyalkanoate synthesis.

Polyhydroxyalkanoates (PHAs) are a diverse class of bio-polymers synthesized by bacteria, usually during imbalanced growth conditions. Optimizing PHA productivity is highly dependent on the bioreactor oxygen transfer rate (OTR), which is an important consideration for process performance and economics, particularly with increasing scale. Relatively few in-depth studies are available regarding the effect of OTR and dissolved oxygen content (DOC) on PHA formation, synthesis rates, composition, and characteristics.

Carbon flux to growth or polyhydroxyalkanoate synthesis under microaerophilic conditions is affected by fatty acid chain-length in Pseudomonas putida LS46.

Economical production of medium-chain length polyhydroxyalkanoates (mcl-PHA) is dependent on efficient cultivation processes. This work describes growth and mcl-PHA synthesis characteristics of Pseudomonas putida LS46 when grown on medium-chain length fatty acids (octanoic acid) and lower-cost long-chain fatty acids (LCFAs, derived from hydrolyzed canola oil) in microaerophilic environments. Growth on octanoic acid ceased when the oxygen uptake rate was limited by the oxygen transfer rate, and mcl-PHA accumulated to 61.

Transcriptomic and proteomic analyses of core metabolism in Clostridium termitidis CT1112 during growth on α-cellulose, xylan, cellobiose and xylose.

Background: Clostridium termitidis CT1112 is an anaerobic, Gram-positive, mesophilic, spore-forming, cellulolytic bacterium, originally isolated from the gut of a wood feeding termite Nasusitermes lujae. It has the ability to hydrolyze both cellulose and hemicellulose, and ferment the degradation products to acetate, formate, ethanol, lactate, H2, and CO2. It is therefore ges in gene and gene product expression during growth of C.