Microbes of biotechnological importance in acidic saline lakes in the Yilgarn Craton, Western Australia

Abstract

Acidic salt lakes are environments that harbor an array of biologically challenging conditions. Through 16S rRNA, 18S rRNA, and ITS amplicon sequencing of eight such lakes across the Yilgarn Craton of Western Australia, we aim to understand the microbial ecology of these lakes with a focus on iron- and sulfur-oxidizing and reducing microorganisms that have theoretical application in biomining industries. In spite of the biological challenges to life in these lakes, the microbial communities were highly diverse. Redundancy analysis of soil samples revealed sulfur, ammonium, organic carbon, and potassium were significant diversities of the microbial community composition. The most abundant microbes with a hypothetical application in biomining include the genus 9 M32 of the Acidithiobacillus family, Alicyclobacillus and Acidiphilium, all of which are possible iron- and/or sulfur-oxidizing bacteria. It is evident through this study that these lakes harbor multiple organisms with potential in biomining industries that should be exploited and studied further.

Keywords: Yilgarn Craton; acidophiles; biotechnology; extremophiles; halophiles; microbial ecology.

Figure 1

Lake sampling locations. Site (A) included Lakes 1 and 2, site (B) included Lakes 3 and 4, and site (C) included Lakes 5, 6, 7, and 8.

Figure 2

(A) Shannon diversity index of the bacterial community grouped by sample type; blue shading represents the distribution of the values plotted. (B) Percentage abundance heatmap of the bacterial phyla grouped by sample type. (C) Percentage abundance heatmap of the bacterial families grouped by sample type. (D) Shannon diversity index of the archaeal community grouped by sample type. (E) Percentage abundance heatmap of the archaeal phyla grouped by sample type. (F) Percentage abundance heatmap of the archaeal families grouped by sample type. Taxonomic levels that constituted less than 3% of any sample type were represented under other.

Figure 3

(A) Non-metric ordination of bacterial microbial communities with a stress score of 0.188. (B) Non-metric ordination of archaeal microbial communities with a stress score of 0.21. (C) Non-metric ordination of the known bacterial iron and sulfur oxidizers/reducers, stress score 0.117, soil sample sites at a depth of 0–10 cm in blue, and soil sample sites at a depth of 20–30 cm in green.

Figure 4

(A) Shannon diversity index of the fungal community grouped by sample type. (B) Shannon diversity index of the eukaryotic community, grouped by sample type. (C) Percentage abundance heatmap of the fungal phyla grouped by sample type. (D) Percentage abundance heatmap of the fungal families grouped by sample type. (E) Percentage abundance heatmap of the eukaryotic phyla grouped by sample type. (F) Percentage abundance heatmap of the eukaryotic families grouped by sample type. Taxonomic levels that constituted less than 4% for ITS and 3% for 18S of any sample type were represented under Other.

Figure 5

(A) Non-metric ordination of fungal microbial communities with a stress score of 0.18. (B) Non-metric ordination of eukaryotic microbial communities with a stress score of 0.20.