A pollution reducing enzymatic deinking approach for recycling of mixed office waste paper.

The efficiency of xylano-pectinolytic enzymes, co-produced by a single microbial strain Bacillus pumilus, was analysed for the recycling of mixed office waste paper through deinking and compared with the alkaline chemical deinking method. Enzymes showed maximum deinking at pH 8.5, pulp consistency of 10%, xylanase-pectinase dose of 12 and 4 IU per gram pulp, respectively, after 120 min of deinking period, and temperature at 50 °C. A chemi-enzymatic approach was employed with xylano-pectinolytic enzymes and various concentrations of deinking chemicals, which showed that enzyme-treated mixed office waste pulp requires only 40% chemicals for deinking, in order to get the almost same level of various handsheets properties, as obtained by the chemical method with 100% chemicals. Similarly, the effluent load of BOD and COD contents was also decreased by 17.90 and 19.75%. This combinational approach of deinking significantly improved the various properties of the handsheets and resulted in gain of 7.5, 9.38, 6.33 and 11.65% in tear factor, burst factor, breaking length and viscosity of the handsheets, while the effective residual ink concentration analysis of deinked handsheets of mixed office waste paper showed deinking efficiency of 22.45%, which revealed the removal of ink particles during enzymatic deinking steps.

An efficient eco-friendly approach for recycling of newspaper waste.

In this study, a chemical reduction strategy was explored for deinking of newspaper waste using xylano-pectinolytic catalysts. A remarkable reduction of 40% in toxic chemicals consumption was obtained by introducing this enzymatic approach of deinking along with improved level of various physical and optical properties. Similarly, a reduction of 18.89% and 17.68% in BOD, COD values of effluent has also been noticed. This combined deinking methodology also resulted in a gain of 5.82% in breaking length, 6.45% in tear factor, 8.57% in burst factor and 9.64% in viscosity, which greatly improved the quality of the handsheets. The study revealed that enzymatic deinking followed by chemical deinking with 40% less chemicals consumption, could be an effective method for reducing the negative impact over the environment caused by 100% deinking chemicals. This is the first report of newspaper waste deinking using xylano-pectinolytic catalysts produced concurrently in the same production media by a bacterial isolate using agricultural wastes as carbon sources.

Improved efficacy of ultrafiltered xylanase-pectinase concoction in biobleaching of plywood waste soda pulp.

The effect of ultrafiltered xylanase-pectinase concoction produced simultaneously by a bacterial isolate using agro-waste-based media was assessed in prebleaching of plywood waste pulp. Ultrafiltered enzymes caused 12.5% reduction in kappa number at reduced enzyme dose of xylanase-pectinase (4.0-0.8 IU) per gram of pulp under optimized conditions at pH 8.5, temperature 55 °C, and treatment period of 2 h. Using this methodology, amount of Cl2-ClO2 consumption can be reduced up to 30 and 28.86%. Significant improvement in physical and optical properties of pulp was obtained along with an additional reduction in BOD and COD values up to 18.13 and 21.66% using this novel biodelignification approach. This is the first report showing the advantages of using ultrafiltered xylanase-pectinase over crude enzymes in enhancing the bleaching capacity of pulp. This study focussing on the development of good quality paper with less pollution generating strategy will definitely prove a boon for industries.

Novel application of fungal Phanerochaete sp. and xylanase for reduction in pollution load of paper mill effluent.

Four different strategies of pulping and bleaching were carried out to develop alternative mechanistic ecoenvironmental friendly approaches and generated effluent was characterised. Strategy-I included Phanerochaete sp. fungal pretreatment followed by conventional bleaching, whereas in strategy-II, fungal pretreatment was followed by enzyme xylanase aided bleaching. Strategy-III also included xylanase supplement but without prior fungal pretreatment. Chemically driven pulping and bleaching was the IV strategy. Conventional C(D)E(OP)D1D2 sequence of bleaching was used for strategy-I and IV whereas XC(D)E(OP)D1D2 sequence was applied to strategy-I and III. Strategy-II was responsible for 27.5% reduction in Kappa no. whereas the maximum (27.5%) reduction in refining energy was observed with strategy-II. Biobleaching strategies-II and III were helpful in saving 37.3 and 20.3% of elemental chlorine (Cl2) and 30.8 and 23.1% of chlorine dioxide (ClO2) respectively. In comparison to control (strategy-IV), strategy II resulted in maximum pollution load reduction of chemical oxygen demand (COD), biological oxygen demand (BOD), color and adsorbable organic halides (AOX) up to 57, 60, 30 and 43.6%, respectively.

An ecofriendly cost effective enzymatic methodology for deinking of school waste paper.

Efficiency of xylano-pectinolytic enzymes in deinking of school waste paper for its reuse has been investigated in the present study. Enzymatic deinked pulp decreased the requirement of chemicals to nearly 50% and gave same optical properties of pulp as obtained by conventional deinking process. This biodeinking plus chemical deinking approach resulted in a decrease of 20.15% and 22.64% in BOD and COD values of effluents and a gain of 10.71% in viscosity, 7.49% in breaking length, 10.52% in burst factor and 6.25% in tear factor as compared to conventional chemical deinking. This is the first report mentioning the use of xylanase and pectinase produced from a cellulase free alkalo-thermotolerant bacterial strain in the same cost effective agricultural residues based production medium for deinking and will help in making the process ecofriendly with 50% reduction in chemicals, commercially viable with better paper quality.