Table 1.

Genetic engineering for heterologous expression of the CAZymes.

Host microorganism	Source Microorganism	Promoter or Genes involved	Enzyme expressed	Yield or enzyme activity	Reference
Bacterial host
Escherichia coli	Erwinia chrysanthemi	CelZ promoter	Endo glucanase	4−6% of total cell protein	[155]
	Cellulomonas fimi	PlacUV5 promoter	Exoglucanase	2−11 times higher yield	[156]
	Clostridium acetobutylicum P262	Native promoter	Endo-1,4-β-d-glucosidase	75 % in periplasmic space	[157]
	Bacteroides succinogenes	Lac promoter	1,3−1,4-β-D-glucan-4-glucanohydrolyase	16.7−22.4 mg of sugar equivalent provided per hour per mg of cell protein	[158]
	Rhodothermus marinus	BglA gene and lac promoter	Thermostable endoglucanase	80 % of activity over range of 75−90 °C	[159]
Zymomonas mobilis	Acetobacter xylinum	Native promoter	Endo-β-1,4-glucanase	75 % in periplasmic space	[160]
	Acidothermus cellulolyticus	Ptac promoter	Endo-β-1,4-glucanase	∼20 % extracellular, ∼30 % in periplasm	[161]
	Ruminococcus albus	gfo gene	β-glucosidase	4.7 % extracellular, 61 % in periplasm	[162]
	Bacillus subtilis	Native promoter	Endo-β-1,4-glucanase	–	[163]
Filamentous fungi as host
Trichoderma reesei	Humicola grisea	Cbh I promoter	xylanase	0.5 g.L−1	[164]
	Chaetomium thermophilum	Cbh I promoter	xylanase	960 U mg−1	[165]
	Penicillium oxalicum	Pdc promoter	GH11 xylanase	1856$\pm$53.5 IU mg−1	[166]
	Acrophialophora nainiana	Bh1 promoter xyn6 gene	GH11 xylanase	172 mgL− 1	[167]
Aspergillus nidulans	Penicillium purpurogenum	α amylase promoter	Acetoxylan esterase (AXE II)	27.4 U mg−1	[168]
	Chaetomium gracile	Native promoter (cgxA and cgxB genes)	Xylanase (cgxA and cgx B)	High level of activity	[168,169]
	Aspergillus niger	AbfA gene	α-l-arabinofuranoside A and B (GH51 and GH54)	0.16−2.63 U/mL culture medium	[170]
Aspergillus oryzae	Aspergillus oculeatus	XegA gene	Xyloglucanase (GH 12)	Specific activity 260 μmol min−1 mg-1 of protein	[171]
	Aspergillus pheonius	Msds genes	1,2-α-mannosidase	Specific activity 3 μmol min−1 mg−1	[172]
Aspergillus niger D15	Aspergillus oculeatus	Man1 gene (gdp promoter)	β-mannase	16,596 nkat min−1	[173]
Yeast as host
Saccharomyces cerevisiae	Agaricus bisporous	gdp promoter (gdp gene)	Glyceraldehyde-3 phosphate dehydrogenase	7.53 g/L of ethanol for 151 g/g orange peel	[173]
Saccharomyces cerevisiae	Trichoderma viride	eg3 and bgl1 genes	Endoglucanase and β-glucosidase	4.63 g/L of ethanol	[174]