title: Anaerobic biotransformation of high concentrations of chloroform by an enrichment culture and two bacterial isolates.
abstract: A fermentative enrichment culture (designated DHM-1) was developed that is capable of cometabolically biotransforming high concentrations of chloroform (CF) to nontoxic end products. Two Pantoea spp. were isolated from DHM-1 that also possess this dechlorination capability. Following acclimation to increasing levels of CF, corn syrup-grown DHM-1 was able to transform over 500 mg/liter CF in the presence of vitamin B(12) (approximately 3% of CF on a molar basis) at a rate as high as 22 mg/liter/day in a mineral salts medium. CO, CO(2), and organic acids were the predominant biodegradation products, suggesting that hydrolytic reactions predominate during CF transformation. DHM-1 was capable of growing on corn syrup in the presence of high concentrations of CF (as may be present near contaminant source zones in groundwater), which makes it a promising culture for bioaugmentation. Strains DHM-1B and DHM-1T transform CF at rates similar to that of the DHM-1 enrichment culture. The ability of these strains to grow in the presence of high concentrations of CF appears to be related to alteration of membrane fluidity or homeoviscous and homeophasic adaptation.
authors.affiliation: CH2MHILL, Atlanta, GA 30328, USA. huifeng.shan@ch2m.com
authors.forename: Huifeng
authors.initials: H
authors.lastname: Shan
authors.forename: Harry D
authors.initials: HD
authors.lastname: Kurtz
authors.forename: Nadia
authors.initials: N
authors.lastname: Mykytczuk
authors.forename: Jack T
authors.initials: JT
authors.lastname: Trevors
authors.forename: David L
authors.initials: DL
authors.lastname: Freedman
mesh_terms: D000693:Anaerobiosis; D001711:Biotransformation; D002245:Carbon Dioxide / Q000378:metabolism; D002248:Carbon Monoxide / Q000378:metabolism; D002264:Carboxylic Acids / Q000378:metabolism; D002713:Chlorine / Q000378:metabolism; D002725:Chloroform / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis; D008969:Molecular Sequence Data; D020636:Pantoea / Q000145:classification / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D014805:Vitamin B 12 / Q000378:metabolism
chemical_list: D002264:Carboxylic Acids; D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D002245:Carbon Dioxide; D002713:Chlorine; D002248:Carbon Monoxide; D002725:Chloroform; D014805:Vitamin B 12