Active Sulfate-Reducing Bacterial Community in the Camel Gut.

Area of Science:

• Microbiology
• Animal Science
• Geochemistry

Background:

• Sulfate-reducing bacteria (SRB) activity in camel gastrointestinal tracts is largely unknown.
• Previous studies indicated abundant SRB in Bactrian camel feces.
• Understanding SRB is crucial for camel gut health and biogeochemical cycling.

Purpose of the Study:

• To investigate the diversity and activity of SRB in Bactrian camel feces.
• To quantify sulfate reduction rates (SRR) in camel feces.
• To identify SRB species and their potential impact on metal availability.

Main Methods:

• Analysis of 55 Bactrian camel fecal samples from the Russian Altai region.
• 16S rRNA gene sequencing for microbial community profiling.
• Radioactive tracer method for measuring SRR.
• Targeted cultivation for isolating SRB pure cultures.
• X-ray diffraction for detecting mineral sulfides.

Main Results:

• High SRR values (0.018–0.168 nmol S cm⁻³ day⁻¹) were measured in camel feces.
• Dominant SRB genera identified were Desulfovibrio and Desulforamulus.
• Chalcopyrite (CuFeS₂) was detected in 36% of samples, indicating metal sulfide precipitation.
• Gypsum was identified as a potential electron acceptor in semi-arid environments.

Conclusions:

• An active SRB community exists in Bactrian camel guts.
• SRB activity influences iron and copper availability through sulfide precipitation.
• Environmental sulfates like gypsum likely serve as electron acceptors for SRB in camel intestines.