Distribution of Phototrophic Purple Nonsulfur Bacteria in Massive Blooms in Coastal and Wastewater Ditch Environments

Abstract

The biodiversity of phototrophic purple nonsulfur bacteria (PNSB) in comparison with purple sulfur bacteria (PSB) in colored blooms and microbial mats that developed in coastal mudflats and pools and wastewater ditches was investigated. For this, a combination of photopigment and quinone profiling, pufM gene-targeted quantitative PCR, and pufM gene clone library analysis was used in addition to conventional microscopic and cultivation methods. Red and pink blooms in the coastal environments contained PSB as the major populations, and smaller but significant densities of PNSB, with members of Rhodovulum predominating. On the other hand, red-pink blooms and mats in the wastewater ditches exclusively yielded PNSB, with Rhodobacter, Rhodopseudomonas, and/or Pararhodospirillum as the major constituents. The important environmental factors affecting PNSB populations were organic matter and sulfide concentrations and oxidation–reduction potential (ORP). Namely, light-exposed, sulfide-deficient water bodies with high-strength organic matter and in a limited range of ORP provide favorable conditions for the massive growth of PNSB over co-existing PSB. We also report high-quality genome sequences of Rhodovulum sp. strain MB263, previously isolated from a pink mudflat, and Rhodovulum sulfidophilum DSM 1374T, which would enhance our understanding of how PNSB respond to various environmental factors in the natural ecosystem.

Production of Hydrogen by Purple Non-Sulfur Bacteria Rhodopseudomonas yavorovii IMV B-7620

“…They inhabit water reservoirs rich in organics or that have a lot of silt, moist soil, saline water. These bacteria are isolated from hot springs and permafrost [28,29]. A wide variety of metabolic pathways was found to allow getting the necessary amount of energy for life processes in the group of purple non-sulfur bacteria.…”

Editorial for the Special Issue: Advances in the Biology of Phototrophic Bacteria

“…This Special Issue highlights recent advances in these aspects. It includes results specifically on green sulfur bacteria (Chlorobi [3]), heliobacteria (Firmicutes [4]), Chloroflexi [5], Cyanobacteria [6,7] and phototrophic purple bacteria (Proteobacteria [8][9][10][11][12][13]). In addition, phylogenetic studies regarding photosynthesis and osmotic adaptation consider representatives of all of these phyla [14,15].…”

“…This Special Issue includes results on identification and genomic characterization of new isolates [9], the adaptation to specific ecological niches in regard to temperature [6], salinity [14] and pH [4]. It also considers aerobic phototrophic purple bacteria and the relations to oxygen and oxidative stress [8][9][10][11]13] as well as environmental interactions [5,7,12] and syntrophic relations [3].…”

“…In colored blooms and microbial mats, phototrophic purple nonsulfur bacteria and purple sulfur bacteria regularly occur together with a clear preference for the purple sulfur bacteria in sulfidic niches. The different niches of phototrophic purple bacteria were highlighted in a comparison of colored blooms in a coastal environment and in wastewater ditches [12]. The sulfidic coastal marine habitat contained purple sulfur bacteria as the major populations, and smaller but significant densities of purple nonsulfur bacteria, with members of Rhodovulum predominating.…”

“…The freshwater/wastewater habitat exclusively yielded purple nonsulfur bacteria, with species of Rhodobacter, Rhodopseudomonas, and/or Pararhodospirillum as the major constituents. As important environmental factors affecting purple nonsulfur bacteria populations, organic matter, sulfide concentrations and the oxidation-reduction potential were identified [12]. Light-exposed, sulfide-deficient water bodies with high content of organic matter and within a limited range of oxidation-reduction potentials provide favorable conditions for the significant growth of purple nonsulfur bacteria [12].…”