Anaerobic Dechlorination by a Humin-Dependent Pentachlorophenol-Dechlorinating Consortium under Autotrophic Conditions Induced by Homoacetogenesis

Mahasweta Laskar, Takanori Awata, Takuya Kasai and Arata Katayama
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Mahasweta Laskar: Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
Takanori Awata: National Institute for Land and Infrastructure Management, Tsukuba 305-0804, Japan
Takuya Kasai: Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
Arata Katayama: Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan

IJERPH, 2019, vol. 16, issue 16, 1-13

Abstract: Anoxic aquifers suffer from energy limitations due to the unavailability of organic substrates, as dictated by hydrogen (H 2 ) for various electron-accepting processes. This deficiency often results in the accumulation of persistent organic pollutants, where bioremediation using organic compounds often leads to secondary contamination. This study involves the reductive dechlorination of pentachlorophenol (PCP) by dechlorinators that do not use H 2 directly, but rather through a reduced state of humin—a solid-phase humic substance—as the extracellular electron donor, which requires an organic donor such as formate, lactate, etc. This shortcoming was addressed by the development of an anaerobic mixed culture that was capable of reductively dechlorinating PCP using humin under autotrophic conditions induced by homoacetogenesis. Here, H 2 was used for carbon-dioxide fixation to acetate; the acetate produced was used for the reduction of humin; and consequently used for dechlorination through reduced humin. The 16SrRNA gene sequencing analysis showed Dehalobacter and Dehalobacterium as the possible dechlorinators, while Clostridium and Oxobacter were identified as the homoacetogens. Thus, this work contributes to the development of an anaerobic consortium that balanced H 2 dependency, where efficiency of humin reduction extends the applicability of anaerobic microbial remediation in aquifers through autotrophy, syntrophy, and reductive dechlorination.

Keywords: autotrophic; H 2; CO 2; humin; acetogens; reductive dechlorination; homoacetogenesis (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2019
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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