Influence of potassium dichromate on the reduction of sulfur, nitrate and nitrite ions by bacteria Desulfuromonas sp.

Author:

Moroz O. M.,Hnatush S. O.,Yavorska H. V.,Zvir G. I.,Tarabas O. V.

Abstract

This article presents the regularities of reduction of sulfur, nitrate and nitrite ions by sulfur reducing bacteria Desulfuromonas sp., which were isolated from the water of the man-made Yavorivske Lake (Lviv Region, Ukraine), under the influence of potassium dichromate. This bacteria in the process of anaerobic respiration can use and reduce different electron acceptors, such as sulfur, nitrates, nitrites, oxidized forms of heavy metals, in particular, hexavalent chromium. Technogenically altered ecotopes are characterized by complex pollution, so several electron acceptors are available to bacteria at the same time. Strains of microorganisms isolated from such ecotopes are adapted to unfavourable conditions and therefore have high biotechnological potential. The purpose of this work was to investigate the regularities of elemental sulfur, nitrate or nitrite ion usage by sulfidogenic bacteria of Desulfuromonas genus in conditions of simultaneous presence in the medium of another electron acceptor – Cr(VI), to establish the succession of reduction of electron acceptors by strains of these bacteria and to evaluate the efficiency of their possible application in technologies of complex purification of the environment from metal compounds and other inorganic toxicants. Bacteria were grown under anaerobic conditions in Kravtsov-Sorokin medium without SO42– and without Mohr’s salt for 10 days. To study the efficiency of sulfur, nitrate or nitrite ions’ reduction at simultaneous presence in the medium of Cr(VI) bacteria were sown in media with elemental sulfur, NaNO3, NaNO2 or K2Cr2O7 to final S0, NO3–, NO2–or Cr(VI) concentration in the medium of 3.47 (concentration of SO42– in medium of standard composition) or 1.74, 3.47, 5.21, 6.94 and 10.41 mM. Biomass was determined by the turbidimetric method, and the concentrations of nitrate, nitrite, ammonium ions, hydrogen sulfide, Cr(VI), Cr(ІІІ) in cultural liquid were determined spectrophotometrically. It has been established that Cr(VI) inhibits the biomass accumulation and hydrogen sulfide production by bacteria of Desulfuromonas sp. after simultaneous addition into the medium of 3.47 mM S0 and 1.74–10.41 mM Cr(VI). In the medium with the same initial content (3.47 mM) of S0 and Cr(VI) bacteria produced Cr(III) at concentrations 3.3–3.4 times higher than that of hydrogen sulfide. It has been shown that K2Cr2O7 inhibits biomass accumulation, nitrate ions’ reduction and ammonium ions’ production by bacteria after simultaneous addition into the medium of 3.47 mM NO3– and 1.74–10.41 mM Cr(VI) or 1.74–10.41 mM NO3– and 3.47 mM Cr(VI). In the medium with the same initial content (3.47 mM) of NO3– and Cr(VI) bacteria reduced up to 1.2 times more nitrate ions than Cr(VI) with the production of ammonium ions at concentrations the same times higher than those of Cr(III). It has been established that K2Cr2O7 inhibits biomass accumulation, nitrite ions’ reduction and ammonium ions’ production by bacteria after simultaneous addition into the medium of 3.47 mM NO2– and 1.74–10.41 mM Cr(VI) or 1.74–10.41 mM NO2– and 3.47 mM Cr(VI). In the medium with the same initial content of (3.47 mM) NO2– and Cr(VI) the reduction of Cr(VI) by bacteria was only slightly, up to 1.1 times, lower than the reduction of nitrite ions, almost the same concentrations of trivalent chromium and ammonium ions were detected in the cultural liquid. The processes of nitrate and nitride reduction carried out by bacteria of Desulfuromonas genus were revealed to be less sensitive to the negative influence of sodium dichromate, as compared with the process of sulfur reduction, because in the media with the same initial content (3.47 mM) of NO3– or NO2– and Cr(VI) bacteria produced 1.1–1.2 times more NH4+ than Cr(III), but in the medium with the same initial content (3.47 mM) of S0 and Cr(VI) ) bacteria produced over than three times more Cr(III) than hydrogen sulfide. Our data allow us to conclude that bacteria of Desulfuromonas genus, the investigated strains of which are adapted to high concentrations (up to 10.41 mM) of inorganic toxicants, play an important role in the geochemical cycles of sulfur, nitrogen and chromium in aquatic environments that have been under anthropogenic influence.

Publisher

Oles Honchar Dnipropetrovsk National University

Subject

General Engineering

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3