Immobilization of pectinase on oxidized pulp fiber and its application in whitewater treatment.

Modified pulp fiber was originally used as a new type of carrier for pectinase immobilization. Pulp fiber was oxidized by sodium periodate to produce aldehyde groups for covalently binding with amino groups of pectinase. Results showed that the enzymatic activity of immobilized pectinase on pulp fiber reached 65 µgg(-1)min(-1) when immobilization pH value, temperature and time were of 7.0, 20 °C and 15 min, respectively. The immobilized pectinase showed higher thermo stability in a wider temperature range of 40-70 °C than its free type and its optimal pH shifted from 8.0 to 8.8. Furthermore, the immobilized pectinase exhibited good operational stability. When employed in whitewater treatment of papermaking industry, it still efficiently decreased the cationic demand after operating repeatedly for six batches. The results obtained demonstrate a promising route to prepare available, cheap and biodegradable carrier for immobilizing enzymes with potential application in wastewater treatment in papermaking industry.

[Measurement of triglyceride content of resin in masson pulp by UV spectral method].

Pitch deposit is one of the most troublesome problems for the paper mills in South China that use the masson pine as a raw material to make paper. The triglyceride has been identified as the main composition accounting for pitch problem. in order to set down effective pitch control scheme, the triglyceride content in papermaking process must be measured quantitatively. A method to measure the content of triglyceride in masson wood pulp was developed based on UV spectrophotometer in the present work. The UV spectrogram and characteristic peak location of standard glycerol trioleate as well as the effect of measuring time on absorbency were discussed. The results showed that at 412 nm the relation between absorbency and consistency of glycerol trioleate was linear and the pertinent coefficient reached 0. 971 in the range of reagent dosage and consistency in this experiment. The absorbency decreased linearly with measuring time and the pertinent coefficient reached 0. 990 2. The results of reproductive experiment showed that the recoveries were 98%-104%0 and the accuracy was 1. 27%-4. 03% for the samples in consistency 1. 25-0. 50 g x L(-1). With this method, the content of triglyceride in hexane extractive of masson TMP and acid SP were measured respectively. The degradative effect of triglyceride before and after enzyme treatment for masson wood pulp was also evaluated. The results showed that the triglyceride content was relatively high, about 50% both in the total extractive of masson TMP and acid SP. After enzyme treatment, the content of triglyceride in masson TMP and acid SP was reduced by 46. 31% and 35. 55% respectively.