Halarchaeum acidiphilum gen. nov., sp. nov., a moderately acidophilic haloarchaeon isolated from commercial solar salt

Abstract

A novel halophilic archaeon, strain MH1-52-1T, was isolated from solar salt imported from Australia. Cells were pleomorphic, non-motile and Gram-negative. Strain MH1-52-1T required at least 3.0 M NaCl and 1 mM Mg2+ for growth. Strain MH1-52-1T was able to grow at pH 4.0–6.0 (optimum, pH 4.4–4.5) and 15–45 °C (optimum, 37 °C). The diether phospholipids phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester, derived from both C20C20 and C20C25 archaeol, were present. Four unidentified glycolipids were also detected. The 16S rRNA gene sequence showed the highest similarity to that of Halobacterium noricense A1T (91.7 %); there were lower levels of similarity to other members of the family Halobacteriaceae. The G+C content of its DNA was 61.4 mol%. Based on our phenotypic, genotypic and phylogenetic analyses, it is proposed that the isolate should be classified as a representative of a new genus and species, for which the name Halarchaeum acidiphilum gen. nov., sp. nov. is proposed. The type strain of Halarchaeum acidiphilum is MH1-52-1T (=JCM 16109T =DSM 22442T =CECT 7534T).

Halomicroarcula pellucida gen. nov., sp. nov., a non-pigmented, transparent-colony-forming, halophilic archaeon isolated from solar salt

“…Tests for catalase and oxidase activities, sole carbon source utilization, hydrolysis of starch, casein, gelatin and Tween 80, indole and H 2 S production, reduction of nitrate and antibiotic sensitivity were performed according to the procedures of Smibert & Krieg (1994), Oren et al (1997) and Minegishi et al (2010a). The results are included in the species description.…”

“…The G+C content of the genomic DNA of strain BNERC31 T , determined by the HPLC method of Tamaoka & Komagata (1984), was 64.1 mol%. The 16S rRNA genes were amplified with a primer set designed from the 59-and 39-terminals and sequenced as described by Minegishi et al (2010a). The sequences of 20 clones suggested that strain BNERC31 T possessed two 16S rRNA genes (GenBank accession numbers AB766179 and AB766180, 1471 bp), with a sequence similarity as low as 94.8 %.…”

“…The temperature range for growth was determined from 10-70 u C (in 5 u C intervals) at 25 % (w/v) NaCl, 10 mM MgCl 2 and pH 7.2. Strain BNERC31 T grew in the range of 20-30 % (w/v) NaCl, 0-500 mM MgCl 2 , pH 6.0-8.5 and 25-55 u C. Optimum growth was observed at 25 % (w/v) NaCl, 10-20 mM MgCl 2 , pH 7.0 and 40 u C. Anaerobic growth with KNO 3 was observed in an anaerobic jar after incubation for 7 days at 40 uC, but no growth was observed with arginine, DMSO or TMAO (trimethylamine N-oxide).Tests for catalase and oxidase activities, sole carbon source utilization, hydrolysis of starch, casein, gelatin and Tween 80, indole and H 2 S production, reduction of nitrate and antibiotic sensitivity were performed according to the procedures of Smibert & Krieg (1994), Oren et al (1997) and Minegishi et al (2010a). The results are included in the species description.…”

Halomarina oriensis gen. nov., sp. nov., a halophilic archaeon isolated from a seawater aquarium

“…At the time of writing, members of the family Halobacteriaceae were classified into 32 genera with over 100 species (Oren et al, 2009;Burns et al, 2010a;Cui et al, 2010a, b;Minegishi et al, 2010;Shimane et al, 2010). Despite the fact that members of the Halobacteriaceae mainly inhabit highsalinity environments where salt concentrations exceed 20 % (Oren, 1994), molecular biological techniques have detected some 16S rRNA gene sequences affiliated with members of the family Halobacteriaceae from low-to moderate-salinity systems (Jurgens et al, 1997;Takai et al, 2001).…”

Halarchaeum nitratireducens sp. nov., a moderately acidophilic haloarchaeon isolated from commercial sea salt

“…A total of 74 strains were purified by repeated streaking, and 16S rRNA gene sequences were determined according to the method of Minegishi et al (2012). Two strains selected for further study, MH1-136-2 T and MH1-370-1, were isolated from commercial solar salt samples made from seawater in Japan and Indonesia, respectively.Phenotypic tests were performed according to the methods of Minegishi et al (2010) and Oren et al (1997). The analyses were conducted using liquid or solidified MH1 medium at 37 u C. Colony morphology was observed on agar medium.…”