Ancharida Akaracharanya

Evaluation of dilute-acid pretreated bagasse, corn cob and rice straw for ethanol fermentation bySaccharomyces cerevisiae

Bagasse, corn cob, and rice straw agricultural wastes were found to consist of 37, 39 and 34% cellulose and 24, 41 and 22% hemicellulose, respectively, on a dry solid (w/w) basis and thus have the potential to serve as a low cost foodstock for ethanol production. Hydrolysates produced by dilute-acid pretreatment followed by cellulase digestion were evaluated as substrates for ethanol fermentation bySaccharomyces cerevisiae. After pretreatment by 141 mM sulphuric acid, bagasse waste released glucose (134 mg/g) at a higher level than that from corn cob (75 mg/g) and rice straw (8 mg/g). Hydroxymethylfurfural (HMF) levels derived from acid pretreatment of bagasse (1.5 g/l), but not corn cob (0.8 g/l) or rice straw (0.1 g/l) attained levels likely to be toxic (1.5 g/l) forS. cerevisiae growth and ethanol fermentation rates. All three agricultural wastes released likely non-toxic levels of furfural (<0.5 g/l) and lactic acid (negligible for bagasse and rice straw and 0.7 g/l for corn cob). After cellulase saccharification of the dilute-acid pretreated agricultural wastes, the glucose content of corn cob hydrolysates (13 ± 0.17 g/l) was marginally higher than that of bagasse (12 ±0.27 g/l) or rice straw (11 ± 0.07 g/l), yet the ethanol conversion yield byS. cerevisiae on corn cob hydrolysate (0.45 ± 0.006 g/g) was lower than that attained with bagasse hydrolysate (0.49 ± 0.007 g/g). Synergistic adverse effects between furfural and HMF with weak acids, or other lignin derived products in the corn cob hydrolysate are proposed as the effective inhibitor (s) for ethanol fermentation byS. cerevisiae.

Cohnella thailandensis sp. nov., a xylanolytic bacterium from Thai soil.

A xylanolytic bacterium, strain S1-3(T), was isolated from soil collected in Nan province, Thailand. It was characterized taxonomically based on phenotypic characteristics and 16S rRNA gene sequence comparison. The strain was a Gram-stain-positive, facultatively anaerobic, spore-forming, rod-shaped bacterium. It contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The major menaquinone was MK-7. Iso-C₁₆:₀ (39.5 %) and anteiso-C₁₅:₀ (26.8 %) were predominant cellular fatty acids. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and lysyl-phosphatidylglycerol were the major polar lipids. The DNA G+C content was 53.3 mol%. Phylogenetic analysis using 16S rRNA gene sequences showed that strain S1-3(T) was affiliated to the genus Cohnella, and was closely related to Cohnella ginsengisoli GR21-5(T) and Cohnella thermotolerans CCUG 47242(T) with 95.7 and 95.3 % sequence similarity, respectively. Strain S1-3(T) could be clearly distinguished from related species of the genus Cohnella by its physiological and biochemical characteristics as well as by its phylogenetic position. Therefore, the strain represents a novel species of the genus Cohnella, for which the name Cohnella thailandensis sp. nov. is proposed. The type strain is S1-3(T) (=KCTC 22296(T) =TISTR 1890(T) =PCU 306(T)).

Paenibacillus thailandensis sp. nov. and Paenibacillus nanensis sp. nov., xylanase- producing bacteria isolated from soil

Two strains of xylanase-producing bacteria, S3-4A(T) and MX2-3(T), isolated from soils in Thailand, were characterized on the basis of their phenotypic and chemotaxonomic characteristics, DNA-DNA relatedness and 16S rRNA gene sequences. The novel strains were Gram-positive, facultatively anaerobic, spore-forming, rod-shaped bacteria. They contained meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The DNA G+C contents of strains S3-4A(T) and MX2-3(T) were 52.7 and 52.9 mol%, respectively. The major isoprenoid quinone was MK-7. The dominant cellular fatty acids were anteiso-C(15 : 0) and iso-C(16 : 0). Phylogenetic analyses using 16S rRNA gene sequences showed that both novel strains were affiliated to the genus Paenibacillus. Strains S3-4A(T) and MX2-3(T) were closely related to Paenibacillus agaridevorans DSM 1355(T) with 97 % and 97.3 % gene sequence similarities, respectively. The DNA-DNA relatedness between strains S3-4A(T), MX2-3(T) and P. agaridevorans DSM 1355(T) was low (6.0-30.3 %). The novel strains could be clearly distinguished from P. agaridevorans DSM 1355(T) by physiological and biochemical characteristics. Therefore, these two strains represent novel species of the genus Paenibacillus, for which the names Paenibacillus thailandensis sp. nov. (type strain S3-4A(T)=KCTC 13043(T)=PCU 275(T)=TISTR 1827(T)) and Paenibacillus nanensis sp. nov. (type strain MX2-3(T)=KCTC 13044(T)=PCU 276(T)=TISTR 1828(T)) are proposed.

Isolation and characterization of arsenic resistant bacteria from tannery wastes and agricultural soils in Thailand.

Highly arsenic resistant bacteria (27 isolates), which had a minimum inhibitory concentrations (MICs) for arsenite and arsenate of ⩾ 40 mM and > 400 mM, respectively, were isolated from tannery wastes and agricultural soils collected in Central Thailand. On the basis of the morphological, cultural, physiological and biochemical characteristics, and on the principal ubiquinone component and 16S rRNA gene sequence analyses, they were identified as nine isolates each ofKlebsiella (Groups 1 and 8) andAcinetobacter (Groups 2, 3 and 7), four isolates each ofPseudomonas (Groups 4 and 6) andComamonas (Group 5), and one isolate ofEnterobacter (Group 9). From these 27 isolates, only one isolate, A3-3 from the genusComamonas, appeared potentially capable of oxidizing arsenite to arsenate, as determined by silver nitrate staining of arsenite agar plates after colony growth.

Cohnella cellulosilytica sp. nov., isolated from buffalo faeces

A cellulose-degrading bacterium, strain FCN3-3(T), was isolated from buffalo faeces collected in Nakhonnayok province, Thailand. The strain was characterized based on its phenotypic and genotypic characteristics. Strain FCN3-3(T) was a Gram-positive, aerobic, spore-forming, rod-shaped bacterium. It contained meso-diaminopimelic acid in cell-wall peptidoglycan. The major menaquinone was MK-7. Anteiso-C(15:0) (52.5%), iso-C(16:0) (18.9%) and C(16:0) (9.1%) were the predominant cellular fatty acids, and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and lysyl-phosphatidylglycerol were the major phospholipids. The DNA G+C content was 58.0 mol%. Phylogenetic analysis using 16S rRNA gene sequences showed that strain FCN3-3(T) was affiliated to the genus Cohnella and was closely related to Cohnella phaseoli GSPC1(T), Cohnella luojiensis HY-22R(T) and Cohnella hongkongensis HKU3(T), with 97.2, 96.8 and 96.3% sequence similarity, respectively. Strain FCN3-3(T) could be clearly distinguished from all known species of the genus Cohnella by its physiological and biochemical characteristics as well as its phylogenetic position and level of DNA-DNA relatedness. Therefore, the strain represents a novel species of the genus Cohnella, for which the name Cohnella cellulosilytica sp. nov. is proposed; the type strain is FCN3-3(T) ( = KCTC 13645(T) = TISTR 1996(T) = PCU 323(T)).

Paenibacillus xylanisolvens sp. nov., a xylan-degrading bacterium from soil.

A xylan-degrading bacterium, strain X11-1(T), was isolated from soil collected in Nan province, Thailand. The strain was characterized based on its phenotypic and genotypic characteristics. Strain X11-1(T) was a Gram-stain-positive, facultatively anaerobic, spore-forming, rod-shaped bacterium. It contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The major menaquinone was MK-7, anteiso-C(15 : 0) (56.6 %) and C(16 : 0) (14.0 %) were the predominant cellular fatty acids and diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine and phosphatidylglycerol were the major phospholipids. The DNA G+C content was 51.6 mol%. Phylogenetic analysis using 16S rRNA gene sequences showed that strain X11-1(T) was affiliated to the genus Paenibacillus and was closely related to Paenibacillus naphthalenovorans KACC 11505(T) and Paenibacillus validus CCM 3894(T), with 96.5 % sequence similarity. Therefore, the strain represents a novel species of the genus Paenibacillus, for which the name Paenibacillus xylanisolvens sp. nov. is proposed. The type strain is X11-1(T) (=KCTC 13042(T) =PCU 311(T) =TISTR 1829(T)).

Cohnella xylanilytica sp. nov. and Cohnella terrae sp. nov., xylanolytic bacteria from soil

Two xylan-degrading bacteria, strains MX15-2(T) and MX21-2(T), were isolated from soils collected in Nan province, Thailand. Cells were Gram-reaction-positive, facultatively anaerobic, spore-forming and rod-shaped. They contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The major menaquinone was MK-7. iso-C(16 : 0) and anteiso-C(15 : 0) were the predominant cellular fatty acids. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and lysyl-phosphatidylglycerol were the major polar lipids. The genomic DNA G+C contents of strains MX15-2(T) and MX21-2(T) were 63.0 and 65.1 mol%, respectively. Phylogenetic analysis using 16S rRNA gene sequences showed that strains MX15-2(T) and MX21-2(T) were affiliated with the genus Cohnella and were closely related to Cohnella thermotolerans CCUG 47242(T), with 96.5 and 95.6 % sequence similarity, respectively. The strains could be clearly distinguished from each other and from all known species of the genus Cohnella based on their physiological and biochemical characteristics as well as their phylogenetic positions and levels of DNA-DNA hybridization. Therefore, these two strains represent novel species of the genus Cohnella, for which the names Cohnella xylanilytica sp. nov. (type strain MX15-2(T) =KCTC 22294(T) =PCU 309(T) =TISTR 1891(T)) and Cohnella terrae sp. nov. (type strain MX21-2(T) =KCTC 22295(T) =PCU 310(T) =TISTR 1892(T)) are proposed.

Salinivibrio siamensis sp. nov., from fermented fish (pla-ra) in Thailand.

A Gram-negative, facultatively anaerobic, moderately halophilic bacterium, strain ND1-1(T), was isolated from fermented fish (pla-ra) in Thailand. The cells were curved rods, motile and non-endospore-forming. The novel strain grew optimally at 37 degrees C, at pH 8 and in the presence of 9-10 % (w/v) NaCl. The predominant respiratory lipoquinone was Q-8. The major cellular fatty acids were C(16 : 0) and C(12 : 0). Polar lipid analysis revealed the presence of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C content was 49.0 mol%. Comparative 16S rRNA gene sequence analyses indicated that strain ND1-1(T) was closely related to Salinivibrio costicola, which comprises three subspecies, and Salinivibrio proteolyticus with gene sequence similarities of 98.3-98.6 %. Strain ND1-1(T) showed low levels of DNA-DNA relatedness with S. costicola subsp. costicola JCM 15095(T) (33.2 %), S. costicola subsp. alcaliphilus DSM 16359(T) (38.4 %), S. costicola subsp. vallismortis JCM 15096(T) (59.7 %), and S. proteolyticus AF-2004(T) (42.1 %). On the basis of the physiological and biochemical characteristics and the molecular data presented, strain ND1-1(T) should be classified as a novel species of the genus Salinivibrio for which the name Salinivibrio siamensis sp. nov. is proposed. The type strain is ND1-1(T) (=JCM 14472(T)=PCU 301(T)=TISTR 1810(T)).

Paenibacillus siamensis sp. nov., Paenibacillus septentrionalis sp. nov. and Paenibacillus montaniterrae sp. nov., xylanase-producing bacteria from Thai soils.

Three strains of xylanase-producing bacteria, S5-3(T), X13-1(T) and MXC2-2(T), isolated from soils in Thailand, were characterized taxonomically based on their phenotypic and chemotaxonomic characteristics and 16S rRNA gene sequence comparisons. They were Gram-positive, facultatively anaerobic, spore-forming, rod-shaped bacteria. They contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The DNA G+C contents were respectively 45.8, 47.3 and 48.8 mol%. The predominant isoprenoid quinone was MK-7, and anteiso-C(15 : 0) and C(16 : 0) were the dominant cellular fatty acids. Phylogenetic analyses based on 16S rRNA gene sequence comparison showed that they were affiliated to the genus Paenibacillus. Strains S5-3(T), X13-1(T) and MXC2-2(T) were closely related to Paenibacillus granivorans A30(T) and Paenibacillus agaridevorans DSM 1355(T) (94.7-98.6 % 16S rRNA gene sequence similarity). The similarity between the three novel strains ranged from 96.3 to 98.4 %. DNA-DNA relatedness, DNA G+C contents and some phenotypic characteristics could clearly distinguish the strains from each other and from related Paenibacillus species. Therefore, strains S5-3(T), X13-1(T) and MXC2-2(T) represent novel species of the genus Paenibacillus, for which the names Paenibacillus siamensis sp. nov. (type strain S5-3(T) =KCTC 13038(T) =PCU 279(T) =TISTR 1831(T)), Paenibacillus septentrionalis sp. nov. (type strain X13-1(T) =KCTC 13039(T) =PCU 280(T) =TISTR 1830(T)) and Paenibacillus montaniterrae sp. nov. (type strain MXC2-2(T) =KCTC 13036(T) =PCU 281(T) =TISTR 1836(T)) are proposed.

Paenibacillus cellulositrophicus sp. nov., a cellulolytic bacterium from Thai soil.

A cellulolytic bacterium, strain P2-1(T), isolated from soil in Thailand, was characterized using a taxonomic approach based on phenotypic and chemotaxonomic characteristics and the 16S rRNA gene sequence. The novel strain was Gram-positive, facultatively anaerobic, spore-forming and rod-shaped. It contained meso-diaminopimelic as the diagnostic diamino acid in the cell-wall peptidoglycan. The DNA G+C content was 52.7 mol%. The major isoprenoid quinone was MK-7. Anteiso-C(15 : 0) and iso-C(16 : 0) were the dominant cellular fatty acids. Phylogenetic analyses using the 16S rRNA gene sequence showed that the novel strain was affiliated to the genus Paenibacillus. Strain P2-1(T) was closely related to Paenibacillus cineris KCTC 3998(T), P. favisporus KCTC 3910(T) and P. rhizosphaerae KCTC 13015(T) with 96.3-96.5 % gene sequence similarity. DNA-DNA relatedness, physiological characteristics and some biochemical characteristics clearly distinguished strain P2-1(T) from related species of the genus Paenibacillus. Therefore, strain P2-1(T) represents a novel species of the genus Paenibacillus, for which the name Paenibacillus cellulositrophicus sp. nov. is proposed. The type strain is P2-1(T) (=KCTC 13135(T)=PCU 305(T)=TISTR 1888(T)).