Microbial production of high octane and high sensitivity olefinic ester biofuels.

Background: Advanced spark ignition engines require high performance fuels with improved resistance to autoignition. Biologically derived olefinic alcohols have arisen as promising blendstock candidates due to favorable octane numbers and synergistic blending characteristics. However, production and downstream separation of these alcohols are limited by their intrinsic toxicity and high aqueous solubility, respectively.

Translating advances in microbial bioproduction to sustainable biotechnology.

Advances in synthetic biology have radically changed our ability to rewire microorganisms and significantly improved the scalable production of a vast array of drop-in biopolymers and biofuels. The success of a drop-in bioproduct is contingent on market competition with petrochemical analogues and weighted upon relative economic and environmental metrics. While the quantification of comparative trade-offs is critical for accurate process-level decision making, the translation of industrial ecology to synthetic biology is often ambiguous and assessment accuracy has proven challenging.

Diversifying Isoprenoid Platforms Atypical Carbon Substrates and Non-model Microorganisms.

Isoprenoid compounds are biologically ubiquitous, and their characteristic modularity has afforded products ranging from pharmaceuticals to biofuels. Isoprenoid production has been largely successful in and with metabolic engineering of the mevalonate (MVA) and methylerythritol phosphate (MEP) pathways coupled with the expression of heterologous terpene synthases. Yet conventional microbial chassis pose several major obstacles to successful commercialization including the affordability of sugar substrates at scale, precursor flux limitations, and intermediate feedback-inhibition.

Optimized gene expression from bacterial chromosome by high-throughput integration and screening.

Chromosomal integration of recombinant genes is desirable compared with expression from plasmids due to increased stability, reduced cell-to-cell variability, and elimination of the need for antibiotics for plasmid maintenance. Here, we present a new approach for tuning pathway gene expression levels via random integration and high-throughput screening. We demonstrate multiplexed gene integration and expression-level optimization for isobutanol production in The integrated strains could, with far lower expression levels than plasmid-based expression, produce high titers (10.

Random Chromosomal Integration and Screening Yields K-12 Derivatives Capable of Efficient Sucrose Utilization.

Chromosomal expression of heterologous genes offers stability and maintenance advantages over episomal expression, yet remains difficult to optimize through site-specific integration. The challenge has in large part been due to the variability of chromosomal gene expression, which has only recently been shown to be affected by multiple factors, including the local genomic context. In this work we utilize Tn5 transposase to randomly integrate a three-gene operon encoding nonphosphotransferase sucrose catabolism into the K-12 chromosome.

Biodiversity Improves Life Cycle Sustainability Metrics in Algal Biofuel Production.

Algal biofuel has yet to realize its potential as a commercial and sustainable bioenergy source, largely due to the challenge of maximizing and sustaining biomass production with respect to energetic and material inputs in large-scale cultivation. Experimental studies have shown that multispecies algal polycultures can be designed to enhance biomass production, stability, and nutrient recycling compared to monocultures. Yet, it remains unclear whether these impacts of biodiversity make polycultures more sustainable than monocultures.

Demonstration of transgressive overyielding of algal mixed cultures in microdroplets.

Algae are ubiquitous in natural ecosystems and have been studied extensively for biofuel production due to their unique metabolic capabilities. Most studies to date have approached biofuel optimization through synthetic biology and process engineering with few industrial scale projects considering algal community interactions. Such interactions can potentially lead to increased productivity and reduced community invasability, both important characteristics for scalable algal biofuel production.