Table 4.

Recent metabolic strategies using native CBP bacteria for biofuel production.

Type of strategy	Product	Titer	Host	Reference
Co-culture	Butanol	7.9 g/L	C. acetobutylicum	Nakayama et al., 2011
			C. saccharoperbutylacetonicum
Co-culture	Acetone	2.64 g/L	C. cellulovorans,	Wen et al., 2014
	Butanol	8.30 g/L	C. beijerinckii
	Ethanol	0.87 g/L
Co-culture	Acetone	4.25 g/L	C. cellulovorans,	Wen et al., 2016
	Butanol	11.5 g/L	C. beijerinckii
	Ethanol	6.37 g/L
Cofactor engineering	Ethanol	40 mM	C. thermocellum	Deng et al., 2013
Cofactor engineering	n-butanol	0.85 g/L	Thermoanaerobacterium saccharolyticum	Bhandiwad et al., 2014
Cofactor engineering	Ethanol	1.60 g/L	C. cellulovorans	Yang X. et al., 2015
	n-butanol	1.42 g/L
Cofactor engineering	Ethanol	5.1 g/L	C. thermocellum	Lo et al., 2017
Elimination competitive pathway	n-butanol	10.0 g/L	C. tyrobutyricum	Yu et al., 2011
Elimination competitive pathway	Ethanol	12.8 mM	Caldicellulosiruptor bescii	Chung et al., 2014
Elimination competitive pathway	Ethanol	37 mM	C. thermocellum	Biswas et al., 2015
Elimination competitive pathway	Ethanol	73.4 mM	C. thermocellum	Papanek et al., 2015
Promoter engineering	Isobutanol	5.4 g/L	C. thermocellum	Lin et al., 2015
RBS engineering	Acetone	21.9 g/L	C. acetobutylicum	Yang et al., 2016
	Butanol
	Ethanol
Pathway modification	1-butanol	29.9 mg/L	Synechococcus elongates PCC1942	Lan and Liao, 2012
Pathway modification	Acetone		C. beijerinckii	Xiao et al., 2012
	Butanol	16.91 g/L
	Ethanol
Pathway modification	Isopropanol	14.63 g/L	C. acetobutylicum	Dusseaux et al., 2013
	Butanol	4.75 g/L
	Ethanol	1.01 g/L
Pathway modification	Acetone	5.4 g/L	C. acetobutylicum	Bormann et al., 2014
	Butanol	16.9 g/L
	Ethanol	3.6 g/L
Pathway modification	1-butanol	–	Methylobacterium extorquens	Hu and Lidstrom, 2014
Pathway modification	n-butanol	15.7 g/L	C. tyrobutyricum	Yu et al., 2015

^aNot reported.