Effect of soot formed in result of coal combustion with two types of solid fuel additives on soot - soil bacteria interaction - biodegradation of soot components by soil bacteria

During coal combustion soot formation is unwanted. There are many fuel additives used to reduce soot production. In this study toxicity and biodegradation of three types of soot by two soil bacteria strains i.e. Pseudomonas aeruginosa and Bacillus subtilis were compared. Two additives were selected to produce soot samples: (i) commonly used and containing significant quantities of NaCl (40-44%) and copper (Cu-additive), (ii) newly developed without NaCl and with triiron tetraoxide instead of copper (Fe additive). Average number of bacterial colonies was similar when soot produced during combustion without additive and with Fe additive were used. It was about 50% higher than number of colonies when soot formed with Cu-additive was applied. The soot biodegradation was tested by HS-GC-MS analysis. The highest biodegradation level (about 80%) was obtained for samples with P. aeruginosa cultures and Fe-additive soot. It can be concluded that newly developed additive does not increase toxicity of the soot to soil bacteria and will be removed more quickly from the environment