supply which is less than 40 g/L could produce more acids than solvents and inhibit
the cells after 48 h of fermentation (Ibrahim et al. 2015).
P2 synthetic medium (P2-Medium) (Monot et al. 1982) is widely used as basic
fermentation medium for Clostridia. P2 synthetic medium consists of vitamin,
mineral and buffer, sugar. This medium is important for cell growth, and solvent
formation. Cell growth is dependent on the presence of Mg, Fe, and K in the
medium. It was reported that, excess of ammonium acetate supplementation caused
acidic fermentation (Monot et al. 1982). Apart from P2 medium, buffer also plays
significant role in modulating the transition between the conversions of acids into
solvents in acetone–butanol–ethanol fermentation. Ibrahim et al. (2015) reported
higher solvent concentration of 2.93 g/L in the ABE fermentation with buffer using
Clostridia as compared to the fermentation without buffer.
4.4.3 Microorganism and Inoculum Preparation
The selection of microorganisms for biobutanol production is important. The
organisms must tolerate toxicity in solvents and concentration of end products.
Commonly, Clostridium sp. are used for the fermentation process. Clostridium
sp. is a group of obligate, Gram-positive, and endospore-forming anaerobes. There
are lots of strains that are commonly used for the fermentation which include ATCC
(American Type Culture Collection), DSM (German Collection of Microorganisms.
Or Deutsche Sammlung Von Mikroorganismen), NCIMB (National Collections of
Industrial & Marine Bactria Ltd.), and NRRL (Midwest Area National Center for
Agriculture Utilization Research, US Department of Agriculture). Though the strains
are different, it still share the similar metabolic pathway and end products.
4.4.4 ABE Fermentation
ABE fermentation was first discovered by Louis Pasteur. He is the first person that
found bacteria producing biobutanol in 1861. Interestingly in 1916, Clostridium
acetobutylicum was first isolated by Chaim Weizmann. He is recognized as the
father of ABE fermentation, and able to ferment sugars into acetone, butanol, and
ethanol. Clostridium sp. was identified as the best organism for ABE fermentation.
Commercial ABE fermentation plant was built in 1918, in Terra Haute, Indiana. This
project supplied butanol for a primary component of paint lacquers (Ezeji et al.
2004). However, during the 1960s, the petrochemical butanol produced seem
unbeatable as a competitor of biologically derived butanol. After decades of the
energy crisis, interest on ABE fermentation was renewed. However, nowadays
China is the only country currently running on ABE fermentation at industrial
scale (Dong et al. 2012).
ABE fermentation continuously gaining interest among researchers to produced
biobutanol with high yield and can tolerate with biobutanol toxicity. ABE fermentation is also feasible and could be a promising process for the second generation
4 Biobutanol Production from Agricultural Biomass
77
the cells after 48 h of fermentation (Ibrahim et al. 2015).
P2 synthetic medium (P2-Medium) (Monot et al. 1982) is widely used as basic
fermentation medium for Clostridia. P2 synthetic medium consists of vitamin,
mineral and buffer, sugar. This medium is important for cell growth, and solvent
formation. Cell growth is dependent on the presence of Mg, Fe, and K in the
medium. It was reported that, excess of ammonium acetate supplementation caused
acidic fermentation (Monot et al. 1982). Apart from P2 medium, buffer also plays
significant role in modulating the transition between the conversions of acids into
solvents in acetone–butanol–ethanol fermentation. Ibrahim et al. (2015) reported
higher solvent concentration of 2.93 g/L in the ABE fermentation with buffer using
Clostridia as compared to the fermentation without buffer.
4.4.3 Microorganism and Inoculum Preparation
The selection of microorganisms for biobutanol production is important. The
organisms must tolerate toxicity in solvents and concentration of end products.
Commonly, Clostridium sp. are used for the fermentation process. Clostridium
sp. is a group of obligate, Gram-positive, and endospore-forming anaerobes. There
are lots of strains that are commonly used for the fermentation which include ATCC
(American Type Culture Collection), DSM (German Collection of Microorganisms.
Or Deutsche Sammlung Von Mikroorganismen), NCIMB (National Collections of
Industrial & Marine Bactria Ltd.), and NRRL (Midwest Area National Center for
Agriculture Utilization Research, US Department of Agriculture). Though the strains
are different, it still share the similar metabolic pathway and end products.
4.4.4 ABE Fermentation
ABE fermentation was first discovered by Louis Pasteur. He is the first person that
found bacteria producing biobutanol in 1861. Interestingly in 1916, Clostridium
acetobutylicum was first isolated by Chaim Weizmann. He is recognized as the
father of ABE fermentation, and able to ferment sugars into acetone, butanol, and
ethanol. Clostridium sp. was identified as the best organism for ABE fermentation.
Commercial ABE fermentation plant was built in 1918, in Terra Haute, Indiana. This
project supplied butanol for a primary component of paint lacquers (Ezeji et al.
2004). However, during the 1960s, the petrochemical butanol produced seem
unbeatable as a competitor of biologically derived butanol. After decades of the
energy crisis, interest on ABE fermentation was renewed. However, nowadays
China is the only country currently running on ABE fermentation at industrial
scale (Dong et al. 2012).
ABE fermentation continuously gaining interest among researchers to produced
biobutanol with high yield and can tolerate with biobutanol toxicity. ABE fermentation is also feasible and could be a promising process for the second generation
4 Biobutanol Production from Agricultural Biomass
77