Diversity of culturable heterotrophic bacteria from the Mariana Trench and their ability to degrade macromolecules

Abstract

The Mariana Trench is the deepest location on earth and harbors unique microbial communities as evidenced by 16S rRNA gene amplicon and metagenomic sequencing. Obtaining culturable microorganisms from the Mariana Trench will contribute to a further understanding of hadal biogeochemical processes and act as a unique microbial reservoir with potential applications. Here, 825 bacterial strains, identified by 16S rRNA gene sequencing, were isolated from 12 water depths (0-10,400 m) of the Mariana Trench with 2216E and R2A media at 4 °C or 28 °C on four cruises during 2015-2017. These bacteria belong to four phyla, nine classes, 27 orders, 45 families and 108 genera. Alphaproteobacteria, Gammaproteobacteria, Actinobacteria_c, Bacilli and Flavobacteriia were the most abundant classes, accounting for 37.9%, 33.0%, 11.8%, 8.6% and 8.0% of the total bacterial isolates, respectively. 2216E and R2A media were found to have a better selectivity to Bacilli and Flavobacteriia, respectively. Fifty strains were potential novel bacterial species with a 16S rRNA gene similarity < 98.65%, and a higher percentage of novel strains were obtained from R2A than 2216E medium. Additionally, 301 (150 species) out of 354 strains (178 species) selected from each depth could degrade at least one of the ten kinds of macromolecules tested. These results indicate that there is a high diversity of culturable bacteria in the Mariana Trench and they can produce a variety of extracellular enzymes. Our study provides a valuable resource of microorganisms for investigating their biogeochemical roles in the Mariana Trench and for industrial applications.

Insights into the Vertical Stratification of Microbial Ecological Roles across the Deepest Seawater Column on Earth

“…The more extreme conditions in the deep sea, especially hydrostatic pressure, do not seem to limit microbial diversity. This is confirmed by the high diversity of culturable bacteria isolated from the deep-sea (>2000 m) in the Mariana Trench [ 61 ]. Notably, compared to 9600 m, the >10,000 m samples showed a decreased number of average MAGs.…”

Marinobacter salinexigens sp. nov., a marine bacterium isolated from hadal seawater of the Mariana Trench

“…Strain ZYF650 T was isolated from the hadal seawater at a depth of 9600 m of the Mariana Trench at station L8 (142°11.5′ N 11°20′ E) during the expedition on the R/V Dong Fang Hong 2 in September 2016 [10,11]. The Mariana Trench is located in the western Pacific Ocean, an average of 200 km to the east of the Mariana Islands, in the Western Pacific east of Philippines and harbours distinctive micro-organisms in the hadal seawater [10,11]. The seawater samples were spread on marine agar 2216E (MA; Becton Dickinson) plates and incubated at the room temperature (approximately 22 °C) on board and 28 °C in the laboratory.…”

“…Meanwhile, anaerobic growth was also examined on MA supplemented with NaNO 2 , KNO 3 , Na 2 SO 4 and Na 2 S 2 O 3 (1.5 g l −1 ) as terminal electron acceptors, respectively, in the jar mentioned above. The temperature range for growth was determined on MA plates as well as in MB tubes by incubating cultures at 0-50 °C (0, 4,10,16,20,24,26,28,32,37,42,45 and 50 °C) for 7 days, and at 0 °C and 4 °C for at least 30 days. In the salinity experiment, distilled water was used to prepare synthetic marine ZoBell broth (per litre: 5 g peptone, 1 g yeast extract and 0.01 g FePO 4 ).…”

Proteases from the marine bacteria in the genus Pseudoalteromonas: diversity, characteristics, ecological roles, and application potentials

“…A 37-1-2 T DQ787199 4-25 6-8 0-9 39 - Khudary et al (2008) Pseudoalteromonas atlantica ATCC T X82134 5-35 5.5-8.5 -40.6-41.7 Casein, gelatin Gauthier et al (1995), Matsushita et al genomic G + C contents of 38-50 mol% (Ivanova et al 1998;Navarro-Torre et al 2020). Strains are also widely distributed in environments from seawater to sediment of a wide range of depths (Zhao et al 2020;Zhou et al 2009Zhou et al , 2013. They are often associated with eukaryotes and produce a range of biologically active agents, such as extracellular enzymes, antibiotics, toxins, and polysaccharides (Bowman 2007;Holmström and Kjelleberg 1999;Ivanova et al 2003;Offret et al 2016;Zhang et al 2016b).…”