Genomic Analysis Unravels Reduced Inorganic Sulfur Compound Oxidation of Heterotrophic Acidophilic Acidicaldus sp. Strain DX-1

Table 2

General features of Acidicaldus sp. strain DX-1 in comparison with other heterotrophic acidophiles.

Organism	Acidicaldus sp. strain DX-1	Acidiphilium cryptum JF-5	Acidiphilium multivorum AIU301	Acetobacter pasteurianus
Isolated from	Acid effusion of mill tailing	Acidic Sediments	Pyritic acid mine drainage	Spontaneous cocoa bean heap fermentation
Temperature range	Moderate thermophilic (50~55°C)	Mesophilic (30~35°C)	Mesophilic (30–35°C)	Mesophilic (25–30°C)
pH range	2.5–3.0	3.0–3.5	3.0–3.5	5.4–6.3
Nutrition type	Heterotrophic	Heterotrophic	Heterotrophic	Heterotrophic
Oxygen requirement	Facultatively anaerobic	Facultatively anaerobic	Facultatively anaerobic	Obligately aerobic
Fe(III) reduction	Yes	Yes	Yes	No
Sulfur oxidation	Yes	No	No	No
Genome size (Mb)	2.99	3.39	3.75	2.91
GC content	68.48%	67.99%	67.58%	53.04%
Protein-coding genes	3259	3063	3448	2875
rRNA operon	1	2	2	5
Number of tRNAs	43	47	48	57