| To study whether soil bacteria can use cellulose and lignin to form humus or not, the pure culture method was utilized. In the study, we research the difference of Humic-like in composition and structure characteristics that was formed by bacteria X1(Brevibacterium sp) and X2(Brevibacterium sp) use different matrix(cellulose and lignin) in places outside soil (pure culture) the experiment condition. So we regarded whole bacteria (mix two kind of bacteria with two kinds of fungi) as CK and utilized the modified method of humus to measurement the quantity and structure characteristics of bacteria and humic-like that was extracted from thallus and to clear the difference and important role of different bacteria, the results can provides scientific basis for soil fertility and soil fixing carbon. The experimental results are as follows:(1) In pure culture of cellulose and lignin from0to60days, the amount of bacteria (X1, X2) was turning in the7th day namely firstly increases and then decreases and it was the28th day for pure culture of lignin. The yield of thallus was continuously increasing.(2) Cellulose and lignin could been degradation by bacteria (X1, X2), molecular structure of metabolite became more complex in later. And adding bacteria treatments promoted drop of C/N, and the role of the X1was the most obvious in pure culture of cellulose, for lignin X2was the most. In pure culture of cellulose, condensation degree was enhanced after added bacteria, whole bacteria’s effect was the largest, and X2was the smallest; For lignin, all treatments made H/C rised, and X1had the greatest effect on it, whole bacteria was the smallest.(3)Carbon content of water soluble substances (WSS)from bacteria in pure culture of cellulose and lignin declined, the bacteria in pure culture of cellulose could increased content of HA-like, and decreased in pure culture of lignin from0to60days. In pure culture of cellulose, humification degree was enhanced after added bacteria, In cellulose pure culture, whether X1or X2, HA-like was formed firstly, then was FA-like, In lignin pure culture, FA-like was formed first-ly for X1, and X2was opposited.(4)In pure culture of cellulose, structure of FA-like became complex in60th day after added bacteria. Adding bacteria was beneficial to formation of nitrogen containing group and reduction of condensation degree from FA-like; X1was more enhanced oxidizability of FA-like than X2. For pure culture of lignin, X1made structure of FA-like more complex, X2had opposite effects from28to60days. At the same time, aromaticity of HS-like after added bacteria was reduced.(5) There were differences in HA properties among different bacteria that using different matrix, and it was different with HA in black soil, but HA in lignin pure culture was more close to HA in black soil. Whether in cellulose pure culture or lignin, structure characteristics of X1in60days was more close to the soil HA than X2.(6) In pure culture of cellulose, X1was beneficial to formation of nitrogen containing group from Hu-like, and the role of bacteria was smaller than whole bacteria. Condensation degrees of Hu after added X2was enhanced, oxidizability of Hu after added X1was reduced. Adding X1formed more HS-like containing aromaticity. Adding X2formed Hu-like was more aliphatic and steady. For pure culture of lignin, aromaticity of whole bacterial Hu-like was the strongest. |
