SE532396C2 - Process for enzymatic decolorization of printed paper - Google Patents

Description

532 396 2 usually contains iron oxide (about 55%), oils (about 5%) and plastic or polymer (website: httgz // wvvweng-tigscom). Various hydrolytic enzymes, such as oellulase, lipase, amylase of bacterial origin or fungal origin, have been used individually or in combination for decolorizing paper waste from offices. (i) Mention may be made of a publication in which a method of decolorizing electrostatically copied and printed paper, collectively referred to as office waste, comprises applying a decolorizing solution to the paper to be decolorized, the decolorizing solution being composed of a cleaning solution and a surfactant of the paperboard. to remove ink from the paper and wash the paper to remove the decolorization solution from the paper (US6022423 dated 2000-02-08). However, this patent involves the use of a special device for decolorizing whole sheets and cannot be used for pulp. (ii) Mention may be made of a publication in which a monocomponent cellulose is used to remove ink and toners from printed papers (US5525193).

The technique of isolating monocomponent cellulases from microorganisms through various purifications, chromatographic steps is time consuming and expensive. (iii) Mention may be made of a publication in which endoglucanase and hemicellulases from a number of fungi are used for efficient decolorization of electrostatically copied paper and laser printed paper (Gubitz et al. 1998). However, the pulp must be treated with surfactants and washed to remove the surface printing ink particles. (iv) A publication may be mentioned in which decolorization of laser-printed or electrostatically copied papers is effected by the use of enzymes containing a resistant binder. The enzyme is added in the specified form to improve speck removal (Patent No. GB 2304741 dated 26.03.97). In the same way as in the references above. the problem remains to remove ink by means of flotation with the technology. (v) Mention may be made of a publication in which decolorization of waste paper from offices is carried out by combining the pulp with a decolorizing agent comprising enzyme cellulase which is preferably active at pH 4 to 8. The treated paper is used in the manufacture of newsprint and high quality paper (patent No. EP 717144 dated 19.06.96). In the same way as in the above-mentioned references, the problem of removing ink by means of totation with the technique remains. 532 398 3 (vi) A publication may be mentioned in which decolorization of waste paper is effected by incubating the pulp with cellulose at 40 ° C under pressure for one hour. Subsequent dissociation of ink particles results in the washed pulp being lighter (Patent No. JP 06346390 dated 20.12.94).

The technology of incubation under pressure and high temperature is an expensive process. (vii) Mention may be made of a publication in which decolorization is effected by using lipases to remove ink from used paper. The process is carried out under neutral or alkaline conditions, in which case regenerated pulp having improved whiteness is produced (Patent No. JP 2160984 dated 20.06.90).

The ink particles are removed by washing and totation. (vili) A publication can be mentioned, in which decolorization of waste paper is done by using the yeast Hansenula polymorpha, which degrades the ink-based resin (patent no. KR 9303705 dated 08.05.93).

However, fl the ink on the surface and the pulp must be washed extensively to remove the separated ink. (ix) A publication may be mentioned in which the decolorization of ink is effected by using thermostable alkaline cellulase from a Bacillus sp (patent number JP10313859). However, this process is very specific to ink. (x) A filed patent may be mentioned in which the decolorization of office waste was accomplished by inoculating the paper pulp with the bacterium Vibrio afgíno / yticum (U.S. Patent Application No. 20030178162). However, the handling of live bacteria is a major drawback in this process and the handling may not be acceptable to many.

SUMMARY OF THE INVENTION The main object of the present invention is to provide a process for enzymatic decolorization of paper waste from offices which paper waste includes electrostatically copied paper and paper printed with ink jet printers which are printed with non-dispersible ink for non-impact printers.

Another object of the present invention is to provide a process for enzymatic decolorization of waste paper from offices which paper waste includes electrostatically copied paper and paper printed with ink jet printers which are printed with non-dispersible ink for non-impact printers using cell culture free cell alopecia. of the same bacterium having access number N10 / D1132 and deposited with the ARS Patent Culture Collection, USA, under number NRRL-B-30638.

The present invention relates to a process for the enzymatic decolorization of paper waste from offices which paper waste includes electrostatically copied paper as well as paper printed with ink jet printers which papers are printed with non-dispersible ink for non-impact printers using cell culture-free cell different which has accession number NIO / Dl / 32 and which is deposited with the ARS Patent Culture Collection, USA, under number NRRL-B-30638. Furthermore, the present invention also relates to the bleaching of pulp of office waste within 72 hours after combining the pulp with a degree of consistency in seawater with 3 - 12% with said enzymes from the said bacteria. Bleaching is accomplished using extracellular enzymes produced by the bacterium N10 / D1132 which is grown in nutrient broth supplemented with starch or polyoxyethylene sorbitan monooleate.

Description of Preferred Embodiments Paper decolorization is a limiting factor in paper recycling. Newsprint and paper waste from offices are usually discolored by the use of chemicals that go down the drain and cause contamination of the water masses. Newspaper printing or offset printing is done by using dispersible printing ink or ink for non-impact printers, while printing ink for laser printers, electrostatic copiers and inkjet printers does not disperse and is also called ink for impact printers. There are a number of patents which describe various methods for decolorizing by the use of hydrolytic enzymes such as cellulase, hemicellulase and lipase of microbial origin which release toner particles from the fibers. However, the enzyme function is affected by the constituents of the paper in the decolorization ratio. The chemically mashed brems are more sensitive than mechanically mashed bres.

Paper waste from offices has a high proportion of lasers and toner in the contents and the technology for removing the toner particles is currently not so good (Jefferies, 2002). We report here a process for decolorizing paper waste from offices that includes electrostatically copied paper and paper prints from inkjet printers using a cell-free culture filtration of a bacterium isolated from marine sediment from a sea arm in Goa, India. the salinity of the water 532 356 at the time of isolation was about 15 parts per thousand which is approximately equivalent to sea water with half salinity.

The organism given in the present invention is Víbrio alginolyticus, a gram-negative, coccoid bacterium isolated from coastal marine sediments and given accession number NIOIDI / 32 and deposited in the ARS patent culture collection center and having accession number NRRL-B-30638.

Said bacterium is grown in a nutrient broth containing meat extract, peptic fusion of animal tissue, prepared with seawater with a salinity diluted to 50% and having a pH value of at least 7.5 and which has been supplemented with 1% starch or 1% Tween -80 solution or both. The bacterium appears during cultivation in nutrient agarnetium as circular colonies with off-white color, which colonies are 2 mm in diameter at the beginning and which grow to a size of 5 mm within 3-4 days. The bacterium produces esterase / lipase and amylase in the presence of Tween-80 and starch, respectively. It is a fermentative and catalase negative bacterium. The bacterium is grown at room temperature (30 ° C) for about 4 days, the culture supernatant accumulates by centrifugation under sterile conditions. Xerox copies, paper printed with inkjet printers or other paper printed with impact ink are distributed to a mass by soaking in warm water for at least 2 hours, macerated in a household mixer with surfactants such as Tween-80. An example of the decolorization process involves suspending such a mass with at least 3-12% consistency in seawater with the salinity diluted to 50%, incubating with supernatant from cell-free culture of said bacterium. The treated mass is incubated at room temperature of 37 ° C for at least 2-3 days to obtain a completely faded mass without traces of ink in the supernatant. The mass is thinned, oxygenated from below to release free contaminant particles and salts. Soap solution at 1% concentration is added to fl otation of residual ink particles. The pulp is filtered under negative pressure through a Buchner funnel, pressed with flat stainless steel plates to give the pulp mat an even thickness. The radiance of the resulting mat is read from 412 to 684 nm and the radiance is expressed in Lux units (Lu). An LU corresponds to a pW / cmz / nm / Sr. The ratio of the radiance between enzymatically decolorized and recycled commercially available paper (hereinafter referred to as the reference paper) is taken as a measure of whiteness.

The metod est methods used for enzymatic decolorization release ink particles from the behöver brema and thus need to be washed away from the pulp. In the process described in the present invention, this problem does not arise when the ink from the toner particles is completely bleached.

The method is very cost effective and the only step involved is fermentation of bacterial inoculum in any conventional nutrient broth which contains assimilable carbon and nitrogen source and which is supplemented with starch or Tween-SO. A comparative presentation is given in Table 1, which explains the novelty of our invention in comparison with known technology in this field.

Table 1. Comparative Preparation Reference Type of Paper Source of Comments (Prior Art) or Ink Dyeing Patent Ink Pressure Ink Chemical and a non-practical large US6022423 and office waste surfactant, scale abrasion of the paper and washing of the decolorized paper by a special device to make a whole sheet US5525193 Toners, Monocomponent- The color particles are released impact ink cellulase purified from from the pulp, but those from mixed cellulolytic must be removed office waste enzymes of various by mechanical microorganisms methods such as and genetically at otation and washing engineered organisms which Gonubantz monok- monok- only cellulase. Xerox Copies and Endogluconases The dye particles are released in 1998 laser prints and hemicellulases from the pulp, but those from fungi must be removed by mechanical methods such as t otation and washing_ 532 355 7 682304741 Laser prints and Enzymes as the Ink floats on xerox copies Cellulas The ink flows on the EP717144 office surface and the pulp must be washed thoroughly JP0634639O Paper waste from [connection with Enzyme high office cellulase at 40 ° C in temperature and pressure one hour below makes the cost of printing technology impractical JP160984 Paper waste from the pulp sat in the printing ink fl surfaces on the office connection with the surface and the mass lipase enzyme underneath must be washed thoroughly neutral or alkaline conditions KR9303705 Paper waste from the mass sat in The printing ink fl surfaces in the office connection with the surface and the mass culture of the yeast must be washed thoroughly Hansenula polymorpha which breaks down the ink-based resin.

JP10313859 For bleaching of Thermostable Recommended for ink alkaline cellulase mixtures with substances from a bacterium surfactant, as a treatment agent and as a decolorizing agent for ink US For decolorization of Living Recommended for attack office waste bacterial culture of decolorization of pulp 532 335 8 no. Vibrio alginolyticus of xerox copies and 200301 78162 inkjet prints.

The use of live bacteria can be unacceptable to many.

Present For pulp Direct contact No enzymes, purification, invention of xerox copies and between mass sludge no temperature or ink jet printing and supernatant pH regulation, the mass of the cell-free and the water is ready the culture of and washing the bacterium is only optional.

N | 0 / D | / 32 for 48 - 72 hours at room temperature. to obtain total bleaching of the pulp and clear wastewater. In accordance with the present invention there is provided a process for enzymatic decolorization of printed papers including xerographically copied papers and inkjet prints printed with non-dispersive ink for non-impact printers: a) culture of the bacterial isolate Vibrio alginolyticus | is deposited with the ARS Patent Culture Collection under NRRL number NRRL-B-30638, in a new medium in a temperature range from 27 ° C to 37 ° C for 3-4 days, b) removal of bacterial cells by central fugue under sterile conditions for to obtain cell culture-free supernatant, c) incubating the pulp of xerographically copied paper or inkjet prints which mass is diluted to 3 - 12% consistency in seawater with salinity diluted to 50% with the cell culture-free supernatant obtained in step (b) at 20% 72 hours at room temperature followed by dilution of the mass tenfold in water to obtain complete slightly bleached pulp without traces of ink in the supernatant, d) filtering the resulting pulp obtained from step (c) under reduced pressure to obtain the desired decolorized paper. In one embodiment of the present invention, the medium is prepared by dissolving nutrient broth containing meat extracts, peptic fusion of animal tissue in seawater with a salinity diluted to 50% and supplemented with polyoxyethylene sorbitan monooleate or 1% starch or both. In another embodiment of the present invention, the bacterium is cultured for at least 4 days in a nutrient broth containing meat extracts, peptic fusion of animal tissue in seawater with a salinity diluted to 50% and supplemented with polyoxyethylene sorbitan monooleate or 1% starch or both.

In a further embodiment of the present invention, sodium chloride with a minimum concentration of 1.5% can be used instead of seawater to grow the bacterium. In a further embodiment of the present invention, the cell-free supernatant used for decolorizing paper contains extracellular enzymes such as esterase, lipase and amylase, etc.

In a further embodiment of the present invention, xerox copies or inkjet prints are soaked in hot water for 1-2 hours after the addition of 1% surfactant followed by maceration to pulp by using a household mixer. In a further embodiment of the present invention, the pulp mat is pressed to make it even and dried at about 60 ° C for at least 4-5 hours. In a further embodiment of the present invention, the radius of the resulting mat is read from 412 to 684 nm and the radiance is expressed in Lux units (LU). A LU corresponds to a pW / cmzlnm / Sr.

In a further embodiment of the present invention, the pulp mat made from recycled paper which is commercially available is used as a reference. In another embodiment of the present invention, the same batch of cell culture-free supernatant can be effectively used for two to three cycles of xerox copy / inkjet printing. In a further embodiment of the present invention, supernatant from freeze-dried culture can also be used effectively for decolorizing said pulp. In a further embodiment of the present invention, bacteria immobilized in sodium alginate droplets can also be used to decolorize the pulp of xerox copies / inkjet prints to obtain fully bleached pulp within 48-72 hours.

The following examples are given by way of illustration and are not to be construed as limiting the scope of the present invention.

EXAMPLE 1 The bacterial isolate Vibño alginolyticus NIO / DI / 32 was isolated from coastal stuarina sediment, Dona Paula, Goa, India in nutrient agar medium containing meat extracts and peptic fusion of animal tissue and agar in seawater with salinity diluted to 50%. The culture was maintained at an angle in the nutrient agar medium during all further experiments.

Said bacterium is grown in nutrient broth containing meat extracts, peptic fusion of animal tissue in seawater with its salinity diluted to 50%. In addition, the medium was changed either with starch or Tween-80 or with both used together at a 1% concentration.

The bacterium is grown at room temperature (30 ° C) for about 4 days, the bacterial cells are removed by centrifugation and the cell culture-free supernatant is used for decolorization purposes. Xerox copies printed with impact ink from HP or Epson or any other printer are distributed to pulp by soaking in warm water for at least 2 hours, as well as maceration in a standard household mixer with surfactants such as Tween-80. An example of the decolorization process involves suspending such pulp at 3, 6 and 9% consistency (g wet pulp in 100 ml of water) to incubate with 50 ml of cell culture-free supernatant prepared as described above and incubating at room temperature for at least 3 days to obtain completely bleached pulp with the ink completely disappeared from the supernatant water. The mass is thinned, oxygenated from below to release free contaminant particles. Soap solution at 1% concentration is added for flotation of residual ink particles. The pulp is filtered under negative pressure through a Buchner funnel, pressed with flat stainless steel plates to give the pulp mat an even thickness. The radiance from the resulting mat is read from 412 to 684 nm and the radiance is expressed in Lux units (Lu). An LU corresponds to a pW / cmz / nm / Sr. The ratio of re ectancy between recycled paper available in any office supplies store (reference paper) and biologically discolored paper is used as a measure of whiteness. The reactance from untreated pulp constitutes a control value. 532 335 11 l accordingly, Figures 1A - 1C show that the refractive power of ink jet printing pulp (untreated) is lower than that of reference paper pulp (commercially available recycled paper). The pulp of printed paper which pulp was treated with the supernatant of the culture containing starch, Tween-80 or both showed a higher radius than the untreated pulp. This whiteness was reached 3 days after incubation with the supernatant of the culture. Accordingly, fi g. 1A, 1B and 1C that treatment with culture filtrate containing fatty acid ester polyoxyethylene sorbitan monooleate gave the highest whiteness. Treatment with culture filtrate with cultures grown with starch or Tween-80 or with both together increased the whiteness much more than the reference pulp (the target value for the whiteness). The radiance of the untreated pulp of printed paper relative to the recycled paper and the radiance of enzymatically discolored paper relative to the pulp of recycled reference paper (Table 1) showed that 6% pulp treated with culture supernatant containing polyoxyethylene sorbitan monooleate showed maximum whiteness.

Table 1. Reflection ratio achieved with different treatments.

Treatment * Reectect ratio% increase (Lux units) *** of reectane 3% pulp Untreated pulp (control value) 0.54 Pulp treated with OF containing 1,04 48 starch "Pulp treated with OF containing 1,39 61 polyoxyethylene sorbitan monooleate" Pulp treated with OF containing 1,29 in 58 starch + polyoxyethylene sorbitan monooleate 6% pulp Untreated pulp (control value) 0.57 Pulp treated with OF containing 1,03 45 starch Pulp treated with OF containing 1,24 64 polyoxyethylene sorbitan monooleate 9% pulp 532 355 12 Untreated pulp (control value) 0.68 Pulp treated with OF containing 0,88 23 starch Pulp treated with OF containing 1,05 35 olyoxyethylene sorbitan monooleate * Culture filtrate (OF) of the bacterium N10 / Dl / 32 grown in nutrient medium in 4 days were added in pulp with different concentrations (VVN).

"Starch or polyoxyethylene sorbitan monooleate was added to the medium at 1% concentration.

*** The reflectance ratio was calculated by dividing the mean reflectance of untreated or treated pulp at different wavelengths by the mean reflectance of reference (target) pulp.

EXAMPLE 2 The aim of the present experiment was to compare mass decolorization using supernatant from bacterial culture containing starch and polyoxyethylene sorbitan monooleate at room temperature and at 37 ° C.

The mass from prints at 3% consistency was incubated with supernatant from bacterial culture containing starch or polyoxyethylene sorbitan monooleate for 72 hours at 37 ° C. At the end of the incubation time, the sludge was filtered out, washed and dried as described in Example 1. The reactance was measured according to the detailed description above. Accordingly, Figures 2A and 2B show that no significant improvements in whiteness occurred at 37 ° C. Table 2 shows the relative average power ratio in different treatments. The result indicates that effective decolorization can be achieved by treatment at room temperature and thereby reduces energy consumption.

Table 2. Reectance ratio achieved by different treatments Treatment * Reectance ratio% increase (3% mass) (Lux units) *** in reectance Untreated mass (control value) at RT 0.54 Mass treated with OF containing 1.04 48 starch ” incubated at RT Mass treated with OF containing 1.39 61 polyoxyethylene sorbitan monooleate * 532 395 13 incubated at RT Mass treated with oF containing 1.29 see starch + polyoxyethylene sorbitan monooleate incubated at RT Untreated (control value) incubated at 37 ° C 0.54 Mass treated with OF containing 1.19 54 starch "incubated at 37 ° C Pulp treated with OF containing 1.14 53 Polyoxyethylene sorbitan monooleate" incubated at 37 ° C Pulp treated with OF containing 1.09 51 starch + polyoxyethylene sorbitan monooleate incubated at 37 ° C C * Culture filtrate (OF) of the bacterium N10 / D1 / 32 grown in nutrient medium for 4 days was added to pulp of different concentrations (WN).

Starch or polyoxyethylene sorbitan monooleate was added to the medium at 1% concentration.

*** The reflectance ratio was calculated by dividing the mean reflectance of untreated or treated pulp at different wavelengths by the mean reflectance of reference (target) pulp.

EXAMPLE 3 To avoid direct contact with the bacterial inoculum, the ability of the immobilized bacterial isolate NIO / DI / 32 to decolorize inkjet prints was performed as follows: Bacterial cells were immobilized in sodium alginate. Briefly, this involved mixing 8 ml of cells (containing 108 cells m | ") with 25 ml of 2% alginic acid (Sigma Chemicals, USA). The droplets were prepared in 0.2 M calcium chloride solution and cured overnight. The same batch of immobilized bacterial cells was used in two cycles to effect decolorization.The other procedures used were the same as described in Example 1.

Accordingly, Figure 3 shows the radiance of bleached pulp after 72 hours of incubation with two cycles of immobilized cells. The ratio of the mean reactance in these two cycles of immobilized cells is shown in Table 3.

It can be concluded that immobilized cells were as effective at decolorization as free bacterial cells. The repeated use of immobilized cells is another advantage.

Table 3. Re ectancy conditions achieved by means of different treatments.

Treatment * Reflection ratio% increase in reflectance (3% mass) (Lux units) *** Untreated 0.54 (control value) at RT Free cells * 1.13 52 immobilized cells, 1.24 56 c cell l ** immobilized cells , 1.09 50 cycles 11 * immobilized cells / free cells of the bacterium N10 / D1 / 32 cultured in nutrient medium for 4 days were added to pulp of different concentrations (WN) - The same batch of immobilized cells was used in two cycles.

“The reflectance ratio was calculated by dividing the mean reflectance of untreated or treated pulp at different wavelengths by the mean reflectance of reference (target) pulp.

EXAMPLE 4 Dyeing of ink jet prints was performed by heat-killed bacterial cells and supernatant from heat-inactivated culture (containing starch or polyoxyethylene sorbitan monooleate). The bacterial cells and supernatants from culture were autoclaved for this purpose at 121 ° C for 15 minutes at 15 lb. The preparation of the mass, inoculum and the experimental set-up and incubation were the same as in previous examples.

Accordingly, Figure 4 shows that at day 3, no decolorization could be achieved using killed bacterial cells and supernatant from heat-inactivated culture, indicating that the active ingredient responsible for the decolorization is heat sensitive.

EXAMPLE 5 The effect of storing supernatant from culture is one of the important criteria for its efficient use. Therefore, supernatant from culture in a natural state, which was stored for 2 days at room temperature, was used to decolorize the mass. For comparative purposes, fresh culture filtrate was used to decolorize the 532,338 pulp. The decolorization procedure was the same as described in Examples 1-4. Accordingly, Figures 5A and 5B show that the stored supernatants lost their effectiveness compared to fresh culture filtrate in decolorization, indicating that the active ingredient involved in decolorization is not is stable when stored at room temperature.

W also compared the efficiency of the freeze-dried culture filtrates during decolorization. Accordingly, Table 4 shows that the lyophilized culture filtrate from medium containing starch or polyoxyethylene sorbitan monooleate could effectively decolorize the pulp.

Table 4. Re ectane ratio in pulp treated with supernatant from lyophilized culture.

Treatment * Reectance ratio% increase in (3K% pulp) (Lux unit rate Reectance Untreated (control value) at 0.54 RT Pulp treated with 1.25 57 lyophilized OF containing starch Mass treated with 1.25 57 lyophilized OF containing polyoxyethylene sorbitan monooleate The lyophilized culture filtrate (OF) was thawed and diluted to the original volume with 50% diluted seawater and incubated with pulp.The control mass was incubated with 50% diluted seawater.

EXAMPLE 6 The active ingredient involved in decolorizing the pulp using supernatant from culture containing starch or polyoxyethylene sorbitan monooleate was examined. Accordingly, amylase and lipase activity in these supernatants were measured. Amylase activity was measured by 1% starch, iodine and potassium iodide (Medda and Chandra 1980).

Lipase activity was measured by modile substrate 4-methylumbelliferyl butyrate (Sigma Chemicals, USA). The fluorescent MUF product released 532 356 16 is measured at excitation and emission wavelengths 364 and 445 nm, respectively (Hoppe H-G. 1993). The use of polyoxyethylene sorbitan monooleate in the medium will induce both esterase and lipase activity (Gupta et al. 2003). Accordingly, the 5-day-old culture filtrate containing starch and polyoxyethylene sorbitan monooleate showed 49 and 33 U ml * activity, respectively. These were the lowest concentrations required for effective decolorization because dilution of the enzyme solution did not show results in effective decolorization. Figure 6 shows the untreated control mass and enzyme treated mass.

Advantages: The main advantages of the present invention are: 1. Cell-free supernatant can be reused for coloring paper waste from offices which paper includes xerox copies and paper prints from ink jet printers printed with non-dispersible ink for non-impact printers. 2. No enzyme purification is required in the present process. No temperature or pH adjustment required.

Claims (7)

5 10 15 20 25 30 35 532 335 17 PATENT REQUIREMENTS A process for enzymatic decolorization of printed paper which includes xerographically copied and ink jet printed paper printed with a dispersible ink for non-impact printers comprising: a) culturing bacterial isolate l / ibrio alginolyticus with accession number NIO / DI / 32, which culture is ARS Patent Culture Collection under NRRL number NRRL-B-30638, in a culture medium prepared in seawater with a salinity diluted to 50% and supplemented with polyoxyethylene sorbitan monooleate or 1% starch or both in a temperature range from 27 ° C to 37 ° C in 3 - 4 days, b) removal of bacterial cells by centrifugation under sterile conditions to obtain cell culture-free supernatant, c) incubation of pulp of xerographically copied and inkjet paper, which pulp is diluted to 3 - 12% consistency in seawater with salinity diluted to 50% with the cell culture-free supernatant obtained in step (b) at 20% concentration in at least 72 hours at room temperature followed by diluting the mass tenfold in water to obtain completely bleached mass without traces of ink in the supernatant, d) filtering the resulting mass obtained from step (c) under reduced pressure to obtain the desired discolored paper. The process of 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 coastal marine sediments from Dona Paula, Goa. A process according to claim 1, wherein sodium chloride at a minimum concentration of 1.5% can be used instead of seawater for culturing said bacterium. The process of claim 1, wherein said xerographically copied or inkjet printed papers are soaked in hot water for 1-2 hours after supplementation with 1% surfactants followed by maceration of the pulp. 10 532 355 18 The process of claim 1, wherein the pulp mat is pressed to make it evenly thick by drying within a temperature range ranging from 25 ° C to 70 ° C for a period of 4-5 hours. The process of claim 1, wherein the same batch of cell culture-free supernatant can be used effectively in two to three cycles of mass decolorization from xerographically copied paper / inkjet paper. A process according to claim 1, wherein the supernatant from lyophilized culture can also be used for efficient decolorization of said pulp.