Alkane and wax ester production from lignin-related aromatic compounds.

Lignin has potential as a sustainable feedstock for microbial production of industrially relevant molecules. However, the required lignin depolymerization yields a heterogenic mixture of aromatic monomers that are challenging substrates for the microorganisms commonly used in the industry. Here, we investigated the properties of lignin-related aromatic compounds (LRAs), namely coumarate, ferulate, and caffeate, in the synthesis of biomass and products in an LRA-utilizing bacterial host Acinetobacter baylyi ADP1.

Synthetic metabolic pathway for the production of 1-alkenes from lignin-derived molecules.

Background: Integration of synthetic metabolic pathways to catabolically diverse chassis provides new opportunities for sustainable production. One attractive scenario is the use of abundant waste material to produce a readily collectable product, which can reduce the production costs. Towards that end, we established a cellular platform for the production of semivolatile medium-chain α-olefins from lignin-derived molecules: we constructed 1-undecene synthesis pathway in Acinetobacter baylyi ADP1 using ferulate, a lignin-derived model compound, as the sole carbon source for both cell growth and product synthesis.

Production of alkanes from CO by engineered bacteria.

Background: Microbial biosynthesis of alkanes is considered a promising method for the sustainable production of drop-in fuels and chemicals. Carbon dioxide would be an ideal carbon source for these production systems, but efficient production of long carbon chains from CO is difficult to achieve in a single organism. A potential solution is to employ acetogenic bacteria for the reduction of CO to acetate, and engineer a second organism to convert the acetate into long-chain hydrocarbons.

Metabolic pairing of aerobic and anaerobic production in a one-pot batch cultivation.

Background: The versatility of microbial metabolic pathways enables their utilization in vast number of applications. However, the electron and carbon recovery rates, essentially constrained by limitations of cell energetics, are often too low in terms of process feasibility. Cocultivation of divergent microbial species in a single process broadens the metabolic landscape, and thus, the possibilities for more complete carbon and energy utilization.

Improved fatty aldehyde and wax ester production by overexpression of fatty acyl-CoA reductases.

Background: Fatty aldehydes are industrially relevant compounds, which also represent a common metabolic intermediate in the microbial synthesis of various oleochemicals, including alkanes, fatty alcohols and wax esters. The key enzymes in biological fatty aldehyde production are the fatty acyl-CoA/ACP reductases (FARs) which reduce the activated acyl molecules to fatty aldehydes. Due to the disparity of FARs, identification and in vivo characterization of reductases with different properties are needed for the construction of tailored synthetic pathways for the production of various compounds.

Proprotein convertase expression in the fat body is essential for a normal antimicrobial peptide response and bacterial host defense.

Invading pathogens provoke robust innate immune responses in Dipteran insects, such as In a systemic bacterial infection, a humoral response is induced in the fat body. Gram-positive bacteria trigger the Toll signaling pathway, whereas gram-negative bacterial infections are signaled the immune deficiency (IMD) pathway. We show here that the RNA interference-mediated silencing of -a member of the proprotein convertase enzyme family-specifically in the fat body, results in a reduction in the expression of antimicrobial peptides.

Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process.

Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long chain alkyl esters. In the first stage, the carbon dioxide is reduced to organic compounds, mainly acetate, in a MES process by Sporomusa ovata.

Twin-layer biosensor for real-time monitoring of alkane metabolism.

Intracellular metabolic sensors can be used for efficient screening and optimization of microbial cell factories. In particular, the sensors are useful in acquiring information about pathway dynamics and bottlenecks in a straightforward manner. Here, we developed a twin-layer biosensor that functions simultaneously at two levels: through transcription factor mediated sensing and enzyme-metabolite interaction, providing insights into the dynamics of alkane metabolism.