Study On The Purification Of Lignin From Pulping Black Liquor By Biological Method

A class of aromatic compounds, lignin, found widely in plants such as gigantopterides and other higher plants. It is abundant, renewable sustainable and cheap. Lignin and or its derivative have many functions, this opened up broad possibilities for use in many sphere, such as dispersant, sorbent, strippant, a substance to help reclaim petroleum, asphalt emulsifier al.. The most important contribution of lignin to sustainable development of the world is that it can provide organic substance steadily and persistently. But, lots of LCC (Lignin-carbohydrate Complexes) in lignin limit the use range of lignin, so it is significant to research the purification of lignin.This paper is based on these points. We fermented lignin from industry with the structure of LCC using microorganism to purify lignin. Using a method called transparent circle, three strains , X1—1, M1—1 and M3-2 with high capacity for degrading hemicellulose were screened. The three strains of microorganism all can produce obvious transparent circle and they all have high activities of hemicellulase , the activities of hemicellulase of X1—1 was as high as 1345. 7 U ? ml^-1, and M1-1,M3-2 was 625.0 U ? ml^-1, 1850. 0 U ? ml^-1 separately. At the same time, experiments indicated that the three strains of microorganism can choose to degrade hemicellulose selectively, but to a large extent they do not make use of lignin.The following we will introduce the properties of hemicellulase produced from the three strains of microorganism. The optimal tempreture for M3-2, Ml-1 and X1-1 were 45℃, 50℃ and 55℃ respectively,and the optimal pH were pH 5, pH 5 and pH 6 respectively. When the tempreture...