Process for enzymatic deinking of printed papers

Abstract

The present invention provides a process for enzymatic deinking of office waste paper inclusive of xerographic and inkjet-printed paper printed with non impact and non dispersible ink using the cell free culture supernatant of Vibrio alginolyticus or immobilized cells of the same bacterium having the accession number NIO/DI/32 and deposited at ARS Patent Culture Collection, USA, under the Number NRRL-B-30638. Further, this invention relates to decolorization of office waste paper pulp within 72 h after contacting the said enzymes from the said bacterium in the pulp of 3-12% consistency in seawater. Decolorization is achieved by using extracellular enzymes produced by the bacterium NIO/DI/32 grown in nutrient broth supplemented with starch or Tween 80.

1 . A process for enzymatic deinking of printed papers inclusive of xerographic and inkjet- printed paper printed with non impact and non dispersible ink comprising:
 a) growing the bacterial isolate  Vibrio alginolyticus  having accession number NIO/DI/32, the culture being deposited at ARS Patent Culture Collection under NRRL Number NRRL-B-30638, in a novel medium at a temperature ranging from 27° C. to 37° C. for 3-4 days;   b) removing the bacterial cells by centrifugation under sterile condition to obtain cell free culture supernatant;   c) incubating the xerox or inkjet-printed paper pulp diluted to 3-12% consistency in sea water with salinity diluted to 50% with the resulting cell free culture supernatant obtained from step (b) at 20% concentration for at least 72 hours at room temp followed by diluting the pulp ten fold in water to obtain completely decolorized pulp without traces of ink in the supernatant;   d) filtering the resulting pulp obtained from step (c) under suction to get the desired deinked paper.   
     
     
         2 . A process according to  claim 1 , wherein the strain used has the following characteristics:
 a) it is a gram negative bacterium;   b) it is a coccoid bacterium isolated from the coastal marine sediments of Dona Paula, Goa.   
     
     
         3 . A process according to  claim 1 , wherein the said novel medium is prepared by dissolving the nutrient broth in sea water with salinity diluted to 50% and supplemented with tween 60 or 1% starch or both. 
     
     
         4 . A process according to  claim 1 , wherein sodium chloride at a minimum concentration of 1.5% can be used in the place of sea water for growing the said bacterium. 
     
     
         5 . A process according to  claim 1 , wherein the xerographic or inkjet-printed paper is soaked in hot water for 1-2 hours after addition of 1% surfactant followed by macerating the pulp. 
     
     
         6 . A process according to  claim 1 , wherein the pulp sheet is pressed to make it uniform followed by drying at temperature ranging from 25° C. to 70° C. for a period of 4-5 hours. 
     
     
         7 . A process according to  claim 1 , wherein the same batch of cell free culture supernatant can be effectively used for two-three cycles of deinking of xerox paper/inkjet-printed paper pulp. 
     
     
         8 . A process according to  claim 1 , wherein the lyophilized culture supernatant can also be effectively used for deinking of the said pulp. 
     
     
         9 . A process according to  claim 1 , wherein bacteria immobilized in sodium alginate beads can also be used for deinking the xerox paper/inkjet printed paper pulp to get completely bleached pulp within 48-72 hours.