Matrix Genetics, Seattle, Washington, United States of America.
PLoS One. 2013;8(3):e58307. doi: 10.1371/journal.pone.0058307. Epub 2013 Mar 11.
We describe how pathway engineering can be used to convert a single intermediate derived from lipid biosynthesis, fatty aldehydes, into a variety of biofuel precursors including alkanes, free fatty acids and wax esters. In cyanobacteria, long-chain acyl-ACPs can be reduced to fatty aldehydes, and then decarbonylated to alkanes. We discovered a cyanobacteria class-3 aldehyde-dehydrogenase, AldE, that was necessary and sufficient to instead oxidize fatty aldehyde precursors into fatty acids. Overexpression of enzymes in this pathway resulted in production of 50 to 100 fold more fatty acids than alkanes, and the fatty acids were secreted from the cell. Co-expression of acyl-ACP reductase, an alcohol-dehydrogenase and a wax-ester-synthase resulted in a third fate for fatty aldehydes: conversion to wax esters, which accumulated as intracellular lipid bodies. Conversion of acyl-ACP to fatty acids using endogenous cyanobacterial enzymes may allow biofuel production without transgenesis.
我们描述了如何通过途径工程将源自脂类生物合成的单一中间产物——脂肪酸醛转化为多种生物燃料前体，包括烷烃、游离脂肪酸和蜡酯。在蓝细菌中，长链酰基-ACP 可以被还原为脂肪酸醛，然后脱羰化为烷烃。我们发现一种蓝细菌类 3 醛脱氢酶 AldE，它是将脂肪酸醛前体氧化为脂肪酸所必需和充分的。该途径中酶的过表达导致脂肪酸的产量比烷烃高出 50 到 100 倍，并且脂肪酸从细胞中分泌出来。酰基-ACP 还原酶、醇脱氢酶和蜡酯合酶的共表达导致脂肪酸醛的第三种命运：转化为蜡酯，蜡酯作为细胞内的脂滴积累。使用内源性蓝细菌酶将酰基-ACP 转化为脂肪酸可能允许在不进行转基因的情况下生产生物燃料。
