Study On The Technology Of Fusion Enzyme Of Xylanase And Cellulase On Mix Ed Office Waste Paper Deinking

In this study, we use cellulase (EGI) and xylanase (Xyn) gene as the fusion object. The thesis focuses on the study of the technology of xylanase/cellulase fusion enzyme on mixed office waste paper (MOW) deinking. At the same time, its deinking effect was compared with cellulase, xylanase and mixed enzyme of them on MOW deinking. The results are as follows:The study found that the best treatment conditions of cellulase was 1.2IU/g for dosage, pH 7.0, enzym atic deinking treatm ent time was 45 m in, temperature 45 ℃. The brightness of the pulp after cellulase deinking can reach 93.6% ISO and its residual ink point can decrease to 178739 (Number/m2). The optimum processing conditions of xylanase was 1.2 IU/g for dosage, p H 7.0, enzymatic deinking treatment time was 60m in, temperature 45 ℃.The brightness of the pulp after xylanase deinking can reach 92.87% ISO and its residual ink point can decrease to 212601 (Number/m2).The optimum processing conditions of mixed enzyme of xylanase and cellulase was that the ratio of xylanase and cellulase was 2:3, p H 7.0, the processing time was 60min, deinking temperature 55 ℃. The brightness of the pulp after mixed enzyme deinking can reach 93.33% ISO and its residual ink point can decrease to 188376 (Number/m2). The best treatm ent conditions of fusion enzyme obtained by gene fusion was 0.6 IU/g for dosage, p H 7.0, enzymatic deinking treatment time was 60min, temperature 55 ℃. The brightness of the pulp after fusion enzyme deinking can reach 94.14% ISO and its residual ink point can decrease to 160058 (Number/m2).The deinking effect of single enzyme, mixed enzyme and fusion enzyme was compared, the effect of fusion enzyme deinking was the best, the deinking effect of mixed enzyme is not necessarily better than single cellulase, single cellulase deinking can achieve very good deinking efficiency. The deinking effect of xylanase was the worst.The study found that the neutral conditions was very conducive to the enzym atic reaction, and too high or too low pH would reduce the activity of relative enzym e, the value of pH should be set at 6.5～7.5. Generally the deinking temperature should be controlled at 40～50℃. Because the deinking of MOW is difficult, its deinking time should be extended and the study found that the deinking time of MOW should be controlled at 45～60 min.