Table 3.

Recent advances in metabolic engineering of diatoms to increase lipid accumulation and production of LC-PUFAs.

approach	gene	species	outcome	references
overexpression	GPAT	P. tricornutum	increase in neutral lipid content and FA	[118]
	FA elongases	T. pseudonana	1.4-fold increase in EPA, 4.5-fold increase in DHA	[119]
	Δ5-elongase	P. tricornutum	8-fold increase in DHA	[120]
	malic enzyme	P. tricornutum	2.5-fold increase in lipid content	[121]
	GPDH	P. tricornutum	increase (60%) in neutral lipid content and MUFAs	[122]
	Δ5-desaturase	P. tricornutum	increase in neutral lipid content and FA	[123]
	DGAT2	P. tricornutum	increase in neutral lipid content	[124]
	acyl-ACP thioesterase	P. tricornutum	increased saturated fatty acids	[125]
	thioesterase	P. tricornutum	increased FA content up to 72%	[126]
	ACCase	C. cryptica, N. saprophila	no change in lipid content, increased (2–3×) ACC activity	[127]
silencing	UGPase	P. tricornutum	increase in lipid content	[128]
	nitrate reductase	P. tricornutum	43% increase in lipid content	[129]
	pyruvate dehydrogenase kinase (PDK)	P. tricornutum	increase (80%) in neutral lipid content	[130]
	multi-functional lipase/phospholipase/acyltransferase	T. pseudonana	increased lipid yields without affecting growth	[131]
targeted genome modification	meganucleases/TALENs disruption of UDP-glucose pyrophosphorylase gene	P. tricornutum	45-fold increase in triacylglycerol accumulation	[132]