Enhanced direct fermentation of cassava to butanol by Clostridium species strain BOH3 in cofactor-mediated medium

Table 2 Performance of different pretreatment method during cassava-based butanol fermentation

Organism	Carbon source	Pretreatment	Butanol (g/L)	Ethanol (g/L)	Acetone (g/L)	Butanol yield (g/g)	Butanol productivity (g/L h)	Solvent productivity (g/L h)	Reference
C. saccharoperbutylacetonicum N1-4	Cassava starch	Enzymatic hydrolysis (commercial enzymes)^a	17.5	1.1	2.7	0.33	0.24	0.30	[9]
Bacillus subtilis WD 161 and C. butylicum TISTR 1032^b	Cassava starch	Coculture	6.7	Approx. 0.9	Approx. 2.1	0.21	0.09	0.14	[7]
C. butyricum TISTR1032	Cassava pulp and cassava wastewater	Enzymatic hydrolysis (commercial enzymes)^c	2.5	1.6	0.6	0.10	–	–	[26]
C. beijerinckii ATCC 55025 and C. tyrobutyricum 25755^d	Cassava starch	Coculture	6.7	1.5	4.0	0.18	0.96	1.93	[24]
C. acetobutylicum PW12	Cassava flour	No pretreatment	12.1	1.9	4.9	0.27	0.13	0.21	[25]
Mutant strain ART18 of C. acetobutylicum PW12	Cassava flour	No pretreatment	16.3	2.4	5.8	0.31	0.19	0.28	[25]
Clostridium. sp. strain BOH3	Cassava flour	No pretreatment	17.8	1.6	4.8	0.30	0.25	0.34	This study

Approx. approximately
^aCommercial enzymes: granular starch hydrolyzing enzymes (α-amylase and glucoamylase)
^bABE and acids (acetic acid and butyric acid) concentrations are 9.7 and 7.3 g/L with yeast extract/NH₄NO₃ ratio of 265/100 (mM/mM) in coculture system, respectively
^cCommercial enzymes: Liquozyme^® SC DS (α-amylase), Spirizyme^® Fuel (glucoamylase), and Novozyme^® NS 50012 (multienzyme complex)
^dImmobilized coculture in two fibrous-bed bioreactors

ISSN: 2731-3654