Hydrocarbon-utilizing microorganisms naturally associated with sawdust

Area of Science:

• Environmental Microbiology
• Bioremediation
• Mycology and Bacteriology

Background:

• Sawdust is a potential sorbent for oil spill cleanup.
• Naturally occurring microorganisms in sawdust can degrade hydrocarbons.
• Understanding microbial communities is crucial for effective bioremediation strategies.

Purpose of the Study:

• To investigate the presence and hydrocarbon-degrading capabilities of fungi and bacteria in sawdust.
• To assess the potential of sawdust-associated microbes for oil bioremediation.

Main Methods:

• Sawdust samples were analyzed for hydrocarbon-utilizing fungi and bacteria.
• Microbial counts (colony forming units, CFU) were determined over six months.
• Fungal and bacterial isolates were identified using 16S rRNA gene sequencing.
• Degradation of crude oil, phenanthrene, and n-hexadecane by pure cultures was quantified.

Main Results:

• Sawdust was initially colonized by hydrocarbon-utilizing fungi (1-2 x 10^5 CFU/g) but lacked bacteria.
• After six months of incubation, fungal counts increased significantly (5-7 x 10^6 CFU/g), and bacteria appeared (8 x 10^4 - 3 x 10^5 cells/g).
• Identified fungi included Candida, Penicillium, and Aspergillus; bacteria included Actinobacterium sp., Micrococcus luteus, and Rhodococcus species.
• Both fungal and bacterial isolates demonstrated the ability to utilize various hydrocarbons as sole carbon sources and degraded crude oil, phenanthrene, and n-hexadecane in batch cultures.

Conclusions:

• Sawdust supports a diverse community of hydrocarbon-degrading fungi and bacteria.
• These microorganisms likely contribute to the bioremediation of oil and hydrocarbon pollutants when sawdust is used as a sorbent.