Date

2019 12:00 AM

Major

Environmental Science; Biology

Department

Geochemistry and Geobiology lab

College

Agriculture and Life Sciences

Project Advisor

Elizabeth Swanner Smith

Description

Photoferrotrophs are photosynthetic bacteria that gain energy from light and utilize Fe(II) as an electron donor, without oxygen, to synthesize organic carbon (i.e. primary productivity). Photoferrotrophs are thought to evolutionarily predate oxygen-producing cyanobacteria and therefore have been important primary producers in Archean oceans. Additionally, ferric iron minerals deposited by photoferrotrophs may have contributed to large iron ore deposits found around the world which are known as Banded Iron Formations (BIF). A bacterium capable of anoxygenic photosynthesis using Fe(II) metabolism was isolated from iron-rich Brownie Lake in Minneapolis, Minnesota. Although photoferrotrophs are capable of utilizing Fe(II), it is not necessarily the only electron donor that they are able to utilize. To better understand the physiological capabilities of the Brownie Lake isolate, growth experiments were conducted with Fe(II) and alternative electron donors including acetate, sulfide, thiosulfate, manganese, and hydrogen gas. In addition to growth measured when utilizing Fe(II), growth was observed when using all alternative electron donors except manganese. The average Fe(II) oxidation rate was 403 μmol L-1 day-1. This rate is commensurate with oxidation rates recorded in studies of other photoferrotrophs and speculated oxidation rates of photoferrotrophs in Archean oceans; this supports the claim that photoferrotrophs contributed to BIF deposition.

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Jan 1st, 12:00 AM

Physiological Characterization of a Novel Photoferrotroph Utilizing Alternative Electron Donors

Photoferrotrophs are photosynthetic bacteria that gain energy from light and utilize Fe(II) as an electron donor, without oxygen, to synthesize organic carbon (i.e. primary productivity). Photoferrotrophs are thought to evolutionarily predate oxygen-producing cyanobacteria and therefore have been important primary producers in Archean oceans. Additionally, ferric iron minerals deposited by photoferrotrophs may have contributed to large iron ore deposits found around the world which are known as Banded Iron Formations (BIF). A bacterium capable of anoxygenic photosynthesis using Fe(II) metabolism was isolated from iron-rich Brownie Lake in Minneapolis, Minnesota. Although photoferrotrophs are capable of utilizing Fe(II), it is not necessarily the only electron donor that they are able to utilize. To better understand the physiological capabilities of the Brownie Lake isolate, growth experiments were conducted with Fe(II) and alternative electron donors including acetate, sulfide, thiosulfate, manganese, and hydrogen gas. In addition to growth measured when utilizing Fe(II), growth was observed when using all alternative electron donors except manganese. The average Fe(II) oxidation rate was 403 μmol L-1 day-1. This rate is commensurate with oxidation rates recorded in studies of other photoferrotrophs and speculated oxidation rates of photoferrotrophs in Archean oceans; this supports the claim that photoferrotrophs contributed to BIF deposition.