They included:(a)knocking out the endogenous fadD gene,which encodes an acyl-CoA synthetase, to block fatty acid degradation;(b)heterologous expression of a plant thioesterase to increase the abundance of shorter chain fatty acids with an eye towards improving fuel quality;(c)increasing the supply of malonyl-CoA by over-expressing ACC and(d)releasing feedback inhibition caused by long-chain fatty acyl-ACPs through overexpression of an endogenous thioesterase.