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The purpose of this study was to develop a novel electrical retrieval method (ER method) for living sponge-associated microorganisms from marine sponges frozen at −80 °C. A −0.3-V vs. Ag/AgCl constant potential applied for 2 h at 9 °C induced the attachment of the sponge-associated microorganisms to an indium tin oxide/glass (ITO) or a gallium-doped zinc oxide/glass (GZO) working electrode. The electrically attached microorganisms from homogenized Spirastrella insignis tissues had intact cell membranes and showed intracellular dehydrogenase activity. Dead microorganisms were not attracted to the electrode when the homogenized tissues were autoclaved for 15 min at 121 °C before use. The electrically attached microorganisms included cultivable microorganisms retrieved after detachment from the electrode by application of a 9-MHz sine-wave potential. Using the ER method, we obtained 32 phyla and 72 classes of bacteria and 3 archaea of Crenarchaeota thermoprotei, Marine Group I, and Thaumarchaeota incertae sedis from marine sponges S. insignis and Callyspongia confoederata. Employment of the ER method for extraction and purification of the living microorganisms holds potential of single-cell cultivation for genome, transcriptome, proteome, and metabolome analyses of bioactive compounds producing sponge-associated microorganisms.

A novel Gram-positive-staining, strictly aerobic and heterotrophic bacterium, designated strain LL-002T, was isolated from organics- and methane-rich seafloor sediment at a depth of 100 m in Kagoshima Bay, Kagoshima, Japan. Colonies were lustreless and translucent white in colour. The temperature, pH and salt concentration ranges for growth were 10–30 °C, pH 6.0–6.5 and 0–1 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain LL-002T belongs to the genus Aneurinibacillus of the family Paenibacillaceae. 16S rRNA gene sequence similarities between strain LL-002T and the type strains of species of the genus Aneurinibacillus were 92.8–95.7 %; the highest sequence identity was with the type strain of Aneurinibacillus migulanus. The DNA G+C content of strain LL-002T was 46.2 mol%. MK-7 was the predominant menaquinone. The predominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0, and the cell-wall peptidoglycan contained meso-diaminopimelic acid and glutamic acid, glycine and alanine in addition to muramic acid and glucosamine. The peptidoglycan type was A1γ. In DNA–DNA hybridization assays between strain LL-002T and the type strains of the other species of the genus Aneurinibacillus, the level of hybridization was 6.3–30.1 %. On the basis of its biological features and the 16S rRNA gene sequence comparison presented here, strain LL-002T is considered to represent a novel species of the genus Aneurinibacillus, for which the name Aneurinibacillus tyrosinisolvens sp. nov. is proposed; the type strain is LL-002T ( = NBRC 110097T = CECT 8536T).