Mohandass C, Raghukumar Chandralata
National Institute of Oceanography, 403004, Dona Paula, Goa, India.
J Ind Microbiol Biotechnol. 2005 Sep;32(9):424-9. doi: 10.1007/s10295-005-0017-8. Epub 2005 Nov 3.
Recycling of office waste paper (photocopy, inkjet, and laser prints) is a major problem due to difficulty in removal of nonimpact ink. Biological deinking of office waste paper is reported using several microorganisms and their enzymes. We report here deinking and decolorization of the dislodged ink particles from inkjet printed paper pulp by a marine bacterium, Vibrio alginolyticus isolate no. NIO/DI/32, obtained from marine sediments. Decolorization of this pulp was achieved within 72 h by growing the bacterium in the pulp of 3-6% consistency suspended in seawater. Immobilized bacterial cells in sodium alginate beads were also able to decolorize this pulp within 72 h. The cell-free culture supernatant of the bacterium grown in nutrient broth was not effective in deinking. However, when the culture was grown in nutrient broth supplemented with starch or Tween 80, the cell-free culture supernatant could effectively deink and decolorize inkjet-printed paper pulp within 72 h at 30 degrees C. The culture supernatant of V. alginolyticus grown in the presence of starch or Tween 80 showed 49 U ml(-1) and 33 U ml(-1) amylase and lipase activities, respectively. Dialysis of these culture supernatants through 10 kDa cut-off membrane resulted in a 35-40% reduction in their efficiency in decolorizing the pulp. It appears that amylase and lipase effectively help in dislodging the ink particles from the inkjet printed-paper pulp. We hypothesize that the bacterium might be inducing the formation of low molecular weight free radicals in the culture medium, which might be responsible for decolorization of the pulp.
办公废纸（复印件、喷墨打印纸和激光打印纸）的回收利用是一个主要问题，因为去除非撞击式油墨存在困难。据报道，利用几种微生物及其酶对办公废纸进行生物脱墨。我们在此报告，从海洋沉积物中分离得到的一株海洋细菌——溶藻弧菌NIO/DI/32，可对喷墨打印纸浆中脱落的油墨颗粒进行脱墨和脱色。将该细菌在浓度为3%-6%、悬浮于海水中的纸浆中培养，72小时内可实现纸浆脱色。固定在海藻酸钠珠中的细菌细胞也能在72小时内使该纸浆脱色。在营养肉汤中培养的该细菌的无细胞培养上清液在脱墨方面无效。然而，当在添加了淀粉或吐温80的营养肉汤中培养时，无细胞培养上清液在30℃下72小时内可有效脱墨并使喷墨打印纸浆脱色。在淀粉或吐温80存在下培养的溶藻弧菌的培养上清液分别显示出49 U ml(-1)和33 U ml(-1)的淀粉酶和脂肪酶活性。通过截留分子量为10 kDa的膜对这些培养上清液进行透析，导致其使纸浆脱色的效率降低35%-40%。看来淀粉酶和脂肪酶有效地帮助从喷墨打印纸浆中去除油墨颗粒。我们推测，该细菌可能在培养基中诱导形成低分子量自由基，这可能是纸浆脱色的原因。
