Study On The Microbial Process Of Shenfu Coal

Because coal is a valuable non-renewable resource, the key issue of coal science and conversion technology is how to effectively utilize structure units of aromatic, heterocyclic, terpenes and pinene in coal. The substrate can be efficiently converted to product by biological catalyst which has high stereo-selectivity to the substrate. On the base of biocatalysis technology, this paper using biological transformation studied the effect of mixed strains and cosubstrate on the biological dissolution of coal, providing a theoretical basis for the oriented bioconversion and the explanation of coal dissolution mechanism in the biological conversion.Base on Shenfu coal treated by photocatalytic oxidation for 6 h (6UV-O-C) and the alkaline extraction residue of 6UV-O-C (I-UV-C), biological conversion of coal samples were studied using bacteria such as Monilia crassa (XK- a), Penicillium citreo viride (XK-b) and Flavobacterium (XK-c) which selected from Shenfu coal-washing wastewater. The effect of hybrid methods of strains on the convention of 6UV-O-C, I-UV-C and humic acid were studied. The results showed that the conversion rates of coal and humic acid by mixed bacteria were worse than single bacteria. The bioconversion rate of 6UV-O-C is higher than I-UV-C, 6UV-O-C and I-UV-C were converted by the mixed strains were composed of XK-a, XK-b and XK-c. The highest total acidic group of humic acid residue converted by mixed strains (XK-a and XK-b) was 7.55 mmol/g, while converted by single strain of XK-a, XK-b and XK-c were 31.13 mmol/g, 27.96 mmol/g, 28.20 mmol/g, respectively. The strains used in this experiment competed with each other, so they were not suitable for mixed culture.Guaiacol, glucose, phenol and veratryl alcohol in different concentrations were added in inorganic salt medium to study the effect of cosubstrate concentration on the XK-a convention of I-UV-C. All four types of cosubstrate promoted the biological dissolution of coal. The XK-a convention rate of I-UV-C was obtained as 27.63 %, 26.81 %, 16.84 %, 10.91 % with the guaiacol, glucose, phenol, veratryl alcohol dosage 0.43 mL/L, 1.0 g/L, 0.5 g/L, 0.29 mL/L respectively. Larger conversion rate of I-UV-C using XK-a, XK-b, XK-c were got in the medium with presence of guaiacol and glucose, as 33.05 %, 27.12 %, 31.77 %, respectively.The conversion products structure was characerized by FTIR and element analysis. FTIR analysis showed that alkaline precipitation products from XK-a convention of I-UV-C contain functional groups such as hydroxy, ether, R-OH, -CH 3 , -CH 2 and aromatic ring. Element analysis showed that H / C ratio and N / C ratio of alkali sediments were 3 to 4 times than those of coal, and H / C ratio of the residual coal from cosubstrate conversion was significantly higher than that in the inorganic salt medium residue, while the N / C ratio decrease. Thermal analysis showed that the thermal stability of residual from cosubstrate convention was worse than that in inorganic salt medium.The dynamics for the convention process of I-UV-C in different cosubstrate using XK-a was studied, and the results showed that the convention process of I-UV-C in different cosubstrate using XK-a was in line with apparent microbial solubilization dynamic model derived from the Avrami-Erofeev equation.