Microbes have been engineered to convert renewable substrates to a wide range of molecules that are ordinarily made from plant oils.
Recently, microorganisms have been engineered to convert simple sugars into several types of biofuels, such as alcohols, fatty acid alkyl esters, alkanes, and terpenes, with high titers and yields.
First, Escherichia coli strains were engineered to convert inexpensive phenylpropanoid acid precursors, 4-coumarate and ferulate to simple coumarins, umbelliferone (4.3 mg/L) and scopoletin (27.8 mg/L), respectively.
The work is of particular interest since the authors introduced a 16:0-ACP desathatse that was engineered to convert 16:0 to 16:1Δ9 with a more than 100-fold higher specificity than that of naturally occurring enzymes.
The genetic tractability, widespread industrial use and endogenous ethanol production capacity of yeast motivate its use [ 28]; however, baker's yeast must be engineered to convert xylose and arabinose.
In their study, a bacterial strain (sender) was engineered to constitutively express alcohol dehydrogenase (ADH), an enzyme that converts ethanol in the medium to acetaldehyde.
In metabolic engineering, xylose isomerase (EC 5.3.1.5) has been traditionally used to convert glucose to fructose in the syrup industry and has recently been engineered to increase the yield of alcohol-based biofuels in S. cerevisiae [ 29].
This result demonstrated that Y. lipolytica could be engineered to produce EPA and suggested that additional engineering improvements were needed to (1) increase the carbon flux into the engineered pathway, (2) improve the efficiency of the C18/20 elongases to convert more GLA into DGLA, and (3) enhance the expression of other pathway genes.
In order to convert laboratory scale fermentation to produce PHAs on an industrial scale, cells must be engineered to make them capable of growing in high density.
The antibodies can also be engineered to contain in-built features that suit various downstream applications [ 19] or converted into functional whole immunoglobulin [ 20, 21].
