Biotechnology Letters 21: 45–48, 1999.
© 1999 Kluwer Academic Publishers. Printed in the Netherlands.
Butanol production by hypersolvent-producing mutant Clostridium
beijerinckii BA101 in corn steep water medium containing maltodextrin
Manish Parekh & Hans P. Blaschek
Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, 132 Animal
Sciences Building, MC-630, 1207 W. Gregory Drive, Urbana, IL 61801, USA
Author for correspondence
Received 21 October 1998; Accepted 24 November 1998
Key words: solvent, butanol, clostridia, corn steep water, maltodextrin
Clostridium beijerinckii NCIMB 8052 parent strain and BA101, a hypersolvent-producingmutant, fermented 6%
(w/v) glucose, maltodextrin,maltose or xylose in a medium containing corn steep water (CSW) to producebutanol.
Batch fermentation in an unoptimized 6% (w/v) maltodextrin plus 1.6% solids CSW medium demonstrated that
C. beijerinckii NCIMB 8052 and BA101 produced 10.7 g butanol/L and 14.5 g butanol/L, respectively.
Butanol is used as a feedstock chemical in the plastic
industry, as a food-grade extractant in the food and
ﬂavor industry, and as a fuel extender. The acetone-
butanol fermentation by clostridia is well known and,
until 1950, the fermentation process was the ma-
jor source of acetone and butanol solvents for the
chemical industry. The increased cost of fermentation
substrates and the availability of cheaper petrochem-
ical feedstocks to synthesize butanol resulted in the
demise of the clostridial fermentation process (Durre
1998). After the oil crisis in 1974, there was a re-
newed interest in the biological production of butanol
by the clostridia. The current studies are focused
on strain improvement, use of economical fermenta-
tion substrates, and on developing an energy-efﬁcient
technology for butanol recovery (Durre 1998).
We have already reported on a Clostridium beijer-
inckii BA101 mutant that produces more butanol than
the NCIMB 8052 wild type strain (Formanek et al.
1997). We also reported the production of butanol by
this mutant in an economical glucose plus corn steep
water (CSW) medium (Parekh et al. 1998a). CSW is
a major byproduct of the corn wet milling process,
and it can be used to supplement vitamins for growth
and solvent productionby C. beijerinckii BA101. This
study focused on evaluation of the CSW medium sup-
plemented with different carbohydrates for acetone-
butanol production by C. beijerinckii BA101 mutant.
Materials and methods
Microorganisms. C. beijerinckii NCIMB 8052 and
BA101 were used in this study. Stock cultures were
maintained as spores in cooked meat medium at 4
Spores were heat-shocked at 80
C for 10 min, and
vegetative cells were grown anaerobically in TGY
(tryptone-glucose-yeast extract) medium at 34
Preparation of medium. The fermentation medium
used contained 6% (w/v) carbohydrate and CSW.
In addition, the medium contained 0.1% (w/v)
cysteine-HCl as a reducing agent, and 0.0012% (w/v)
O. A single batch of CSW was used for
preparation of the fermentation medium. 10% solids
CSW (A. E. Staley Manufacturing Company, Decatur,
IL) was pre-treated as follows. To raw CSW (pH 4.2),
cysteine-HCl was added followed by adjustment of
and was centrifuged the following day at 27 500 × g
for 60 min at 4
C. The clear CSW supernatant ob-
tained after centrifugation was diluted with distilled
water to achievethe desired 1.6% solids concentration.