Microbial production of fatty-acid-derived fuels and chemicals from plant biomass

Abstract

Increasing energy costs and environmental concerns have emphasized the need to produce sustainable renewable fuels and chemicals. Major efforts to this end are focused on the microbial production of high-energy fuels by cost-effective 'consolidated bioprocesses'. Fatty acids are composed of long alkyl chains and represent nature's 'petroleum', being a primary metabolite used by cells for both chemical and energy storage functions. These energy-rich molecules are today isolated from plant and animal oils for a diverse set of products ranging from fuels to oleochemicals. A more scalable, controllable and economic route to this important class of chemicals would be through the microbial conversion of renewable feedstocks, such as biomass-derived carbohydrates. Here we demonstrate the engineering of Escherichia coli to produce structurally tailored fatty esters (biodiesel), fatty alcohols, and waxes directly from simple sugars. Furthermore, we show engineering of the biodiesel-producing cells to express hemicellulases, a step towards producing these compounds directly from hemicellulose, a major component of plant-derived biomass.

Functional expression and characterization of five wax ester synthases in Saccharomyces cerevisiae and their utility for biodiesel production

“…WS/DGAT from Acinetobacter baylyi ADP1 has been adopted in E. coli for ester production [4,8,16-18]. WS homologs are frequently found in the genomes of actinomycetes such as Rhodococcus [19,20] or in the genome databases of several marine bacteria like Marinobacter [19,21] and Psychrobacter [19].…”

“…As shown in Figure 1, WS can catalyze the formation of FAEEs (as in biodiesel) from ethanol and fatty acyl-CoA, and here this strategy was used to construct proof of principle biodiesel microbial cell factories that could ultimately form the basis for large-scale commercial biodiesel production and result in a fully sustainable fuel [3,16,23]. Previously reported renewable diesel cell factories have been mainly developed in the model organism E. coli , by expressing WS from A. baylyi ADP1, a bifunctional enzyme functioning as WS and DGAT and encoded by the gene a tfA [8,16-18].…”

“…Previously reported renewable diesel cell factories have been mainly developed in the model organism E. coli , by expressing WS from A. baylyi ADP1, a bifunctional enzyme functioning as WS and DGAT and encoded by the gene a tfA [8,16-18]. However, the activity of WS from A. baylyi ADP1 for short-chain alcohols and the ability to form biodiesel is poor, which is one of the major limitations for biodiesel production.…”

Cloning of a Family 11 Xylanase Gene from Bacillus amyloliquefaciens CH51 Isolated from Cheonggukjang

“…Family 5,7,8,or 43 xylanases are also known but not much informations are available [1]. High crude oil prices drive development of alternative energy sources including bioenergy [4]. Isolation of microorganisms utilizing xylan efficiently is important since xylan occupies a significant portion of utilizable polymers in plants [4].…”

Metabolic manipulation of methanogens for methane machinations

“…The U.S.A is moving toward energy independence; a distant memory are the long lines for gasoline of the 1970s and fading is the promise of competitive biofuels from Escherichia coli (Liu and Khosla, 2010; Steen et al ., 2010). The reason is cheap methane.…”