Hg tolerance and biouptake of an isolated pigmentation yeast Rhodotorula mucilaginosa

• Published in: PloS one Vol. 12; no. 3; p. e0172984
• Main Authors: Liu, Bing, Wang, Chaogang, Liu, Danxia, He, Ning, Deng, Xu
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02.03.2017; Public Library of Science (PLoS)
• Subjects: Bacteria; Binding; Bioaccumulation; Bioavailability; Biological Availability; Biology and Life Sciences; Bioremediation; Carboxyl group; Ecology; Functional groups; Heavy metals; Hydroxyl groups; Laboratories; Lag phase; Life sciences; Medicine and Health Sciences; Mercury; Mercury (metal); Mercury - metabolism; Mercury - toxicity; Mercury poisoning; Molecular weight; Oceanography; Phosphates; Photoelectron Spectroscopy; Phylogenetics; Phylogeny; Physical Sciences; Physiological aspects; Pigmentation; Research and Analysis Methods; Rhodotorula; Rhodotorula - genetics; Rhodotorula - metabolism; Rhodotorula mucilaginosa; Ribosomal DNA; RNA, Ribosomal - genetics; Studies; X ray photoelectron spectroscopy; Yeast; Yeasts (Fungi); United States
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0172984

A pigmented yeast R1 with strong tolerance to Hg2+ was isolated. Phylogenetic identification based on the analysis of 26S rDNA and ITS revealed R1 is a Rhodotorula mucilaginosa species. R1 was able to grow in the presence of 80 mg/L Hg2+, but the lag phase was much prolonged compared to its growth in the absence of Hg2+. The maximum Hg2+ binding capacity of R1 was 69.9 mg/g, and dead cells could bind 15% more Hg2+ than living cells. Presence of organic substances drastically reduced bioavailability of Hg2+ and subsequently decreased Hg2+ removal ratio from aqueous solution, but this adverse effect could be remarkably alleviated by the simultaneous process of cell propagation and Hg2+ biouptake with actively growing R1. Furthermore, among the functional groups involved in Hg2+ binding, carboxyl group contributed the most, followed by amino & hydroxyl group and phosphate group. XPS analysis disclosed the mercury species bound on yeast cells was HgCl2 rather than HgO or Hg0.