title: Microbial community profiling of the Chinoike Jigoku ("Blood Pond Hell") hot spring in Beppu, Japan: isolation and characterization of Fe(III)-reducing Sulfolobus sp. strain GA1.
abstract: Chinoike Jigoku ("Blood Pond Hell") is located in the hot spring town of Beppu on the southern island of Kyushu in Japan, and is the site of a red-colored acidic geothermal pond. This study aimed to investigate the microbial population composition in this extremely acidic environment and to isolate/characterize acidophilic microorganism with metal-reducing ability. Initially, PCR (using bacteria- and archaea-specific primers) of environmental DNA samples detected the presence of bacteria, but not archaea. This was followed by random sequencing analysis, confirming the presence of wide bacterial diversity at the site (123 clones derived from 18 bacterial and 1 archaeal genera), including those closely related to known autotrophic and heterotrophic acidophiles (Acidithiobacillus sp., Sulfobacillus sp., Alicyclobacillus sp.). Nevertheless, successive culture enrichment with Fe(III) under micro-aerobic conditions led to isolation of an unknown archaeal organism, Sulfolobus sp. GA1 (with 99.7% 16S rRNA gene sequence identity with Sulfolobus shibatae). Unlike many other known Sulfolobus spp., strain GA1 was shown to lack sulfur oxidation ability. Strain GA1 possessed only minor Fe(II) oxidation ability, but readily reduced Fe(III) during heterotrophic growth under micro-aerobic conditions. Strain GA1 was capable of reducing highly toxic Cr(VI) to less toxic/soluble Cr(III), demonstrating its potential utility in bioremediation of toxic metal species.
authors.affiliation: Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. Electronic address: y-masaki11@mine.kyushu-u.ac.jp.
authors.forename: Yusei
authors.initials: Y
authors.lastname: Masaki
authors.affiliation: Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. Electronic address: k-tsutsumi@mine.kyushu-u.ac.jp.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Tsutsumi
authors.affiliation: Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Chiba 270-1194, Japan. Electronic address: s-hirano@criepi.denken.or.jp.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Hirano
authors.affiliation: Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. Electronic address: okibe@mine.kyushu-u.ac.jp.
authors.forename: Naoko
authors.initials: N
authors.lastname: Okibe
mesh_terms: D000332:Aerobiosis; D058448:Biota; D002857:Chromium / Q000378:metabolism; D016000:Cluster Analysis; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005290:Ferric Compounds / Q000378:metabolism*; D045482:Hot Springs / Q000382:microbiology*; D007564:Japan; D010084:Oxidation-Reduction; D010802:Phylogeny; D061005:Ponds; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D016944:Sulfolobus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism
chemical_list: D019641:DNA, Archaeal; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005290:Ferric Compounds; D012336:RNA, Ribosomal, 16S; D002857:Chromium; D013455:Sulfur
keywords: Acidophile; Cr(VI) reduction; Extreme environment; Fe(III) reduction; Microbial diversity; Sulfolobus