Process for bio-bleaching of Kraft pulp using bacterial consortia

A method of bio-bleaching Kraft pulp using bacterial strains of accession no. MTCC 5096, MTCC 5094, MTCC 5095, and MTCC 5098, said method comprising the steps of:

• a. inoculating the pulp suspension with an inoculum of the bacterial strain MTCC 5096 having xylanase activity as stage one,
• b. incubating the inoculated pulp for about 15–20 hours at about 100–120 rpm at about 26–32° C.,
• c. adding sodium hydroxide and hydrogen peroxide to the inoculated pulp of step (b) for alkali extraction as stage two,
• d. incubating the pulp at about 65–70° C. for about 1.5–2.5 hrs,
• e. filtering the pulp and washing with sterile distilled water,
• f. suspending the washed pulp in fresh minimal salt medium,
• g. inoculating the pulp suspension with the consortium comprising ligninolytic bacterial strains of accession no. MTCC 5094, MTCC 5095, and MTCC 5098 as stage three,
• h. incubating the inoculated pulp of step (g) for about 15–20 hrs at about 100–120 rpm at about 26–32° C. at a pH of about 5–9,
• i. repeating the steps (b) to (e) with alkali extraction as stage 4 to obtain pulp with a percent brightness of about 17%.