Newspaper enzymatic digestibility

Enhancement of Enzymatic Digestibility of Recycled Newspaper by Addition of Surfactant in Ammonia-Hydrogen Peroxide Pretreatment... 

Index Entries Pretreatment newspaper ammonia hydrogen peroxide enzymatic digestibility surfactant. 

Cellulose, the major component of wastepaper, can be transformed into fennentable sugars by enzymatic hydrolysis. Newspaper is mostly derived fi om softwood and exhibits low enzymatic digestibility because of its high lignin content and dense structure. Additionally, chemicals such as fillers, ink, and other additives make it difficult to hydrolyze enzymatically. Thus, effective preh-eatment is n ded to increase enzymatic hydrolysis of newspaper. 

In this chapter we discussed our previous studies briefly and presented ongoing studies about the pretreatment and enzymatic digestibility of used newspaper. 

Figure 1. Enzymatic digestibility of newspaper, office paper and corrugated paper treated with 4 wt% ammonia and 2 wt% H2O2 solution.

Figure 3. Effect ofNP-5 loading in 4 wt% ammonia solution on enzymatic digestibility of newspaper.

Figure 5. Effect of input stage ofNP-5 on enzymatic digestibility of newspaper. (1 4 w1% ammonia and NP-5 add together in pretreatment stage, 2 4 wt% ammonia adds in pretreatment stage and then NP 5 in hydrolysis stage.)...

Pretreated samples in our study were washed with water until neutralized to pH 7.0, but this step required a lot of water, about 300 times the weight of substrate used, because the pretreated sample was sticky and swollen. It was theorized that there was still a small amount of surfactant left in the washed fibers, and that residual surfactant may help enzymatic hydrolysis. Figure 4 shows the effect of residual surfactant after pretreatment on digestibility at 72 h. To see this effect, newspaper was pretreated without surfactant, and then a given amount of surfactant was added to... 

We investigated factors that affect enzymatic hydrolysis of newspaper, such as ash content, substrate size, and ink (10). Results sho d that ink had a significant effect on en2ymatic digestibility, whereas ash content and substrate size had a very small effect. Therefore, it was concluded that ink removal from newspaper is prerequisite for en2ymatic hydrolysis. 

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