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Sustainable fuel and chemicals production from CO
2
as CO based bioeconomy
by Clostrdium thailandense 2

Sompong O-Thong

International college, Thaksin University, Songkhla, 90000 Thailand
___________________________________________________________________________

Abstract
Homoacetogens consortium was enriched from peatland soil, digested sludge, and
rumen fluid for simultaneous carbon dioxide (CO ) consumption and acetic acid production
2
in the biogas upgrading process. The homoacetogens consortium enriched from peatland soil
%
(PL3) has a maximum CO consumption and acetic acid production of 95 and 120 mg/L,
2
respectively. The methane content in upgraded biogas and acetic acid production of 98% and
543.4 mg/L was obtained at optimum hydrogen (H ) to CO at a ratio of 2:1, pH 8, and
2
2
%
temperature 30 C. The upgraded biogas (CH >95 ) can be used as vehicle fuel or injected
o
4
into the natural gas grid. The homoacetogens consortium PL3 was dominated by Clostridium
.
sp., Proteiniclasticum sp., and Petrimonas sp Clostridium sp While Clostridium species are

.

the main homoacetogens responsible for CO reduction using H as an energy source The
.
2
2
homoacetogens consortium PL3 could provide an opportunity for simultaneous biogas
upgrading to biomethane and acetic acid production. An acetogenic, obligately anaerobic,
T
Gram- positive, endospore- forming bacterium, designated strain PL3 , was isolated from
T
peatland soil enriched with H and CO . Cells of strain PL3 were 0.8-1.0 x 4.0-10.0 m, straight
2
2
T
rod-shaped, with sup-terminal endospores. Growth of PL3 occurred at pH 6-7 (optimum, pH
)
o
7), temperature of 25-35 C (optimum, 30 C), and 0-1.5% (w/v NaCl (optimum, 0.5%).
o
T
Biochemical analyses revealed that strain PL3 metabolized lactose, maltose, raffinose,
rhamnose, lactic acid, sorbitol, arabinose, and glycerol Acetic acid and ethanol were the
.
.
predominant products from H / CO fermentation The genomic in silico DNA- DNA
2
2
T
T
hybridization value between strain PL3 and C. aciditolerans DSM 17425 was 25.1%, with the
average nucleotide identity (ANI) value of 80.2%. Based on the phenotypic, chemotaxonomic,
and phylogenetic differences with concurrent low genomic identity to other species, strain
T
name Clostridium
PL3 is suggested to represent a novel species within the genus Clostridium
sp. nov. is proposed. The type strain is PL3 (=DSM 111812 = TISTR 2984 ).
thailandense T T T

Keywords: CO economy, biogas upgrading, acetic acid production, homoacetogens
2