생명과학회지 (Journal of Life Science)

  • 제18권11호
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  • Pages.1617-1624
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  • 2008
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  • 1225-9918(pISSN)
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  • 2287-3406(eISSN)
한국생명과학회 (Korean Society of Life Science)
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키틴/키토산 가수분해효소의 분류 및 특성

Classification and Characteristics of Chitin/Chitosan Hydrolases

  • 이한승 (신라대학교 의생명과학대학 바이오식품소재학과)
  • Lee, Han-Seung (Department of Bio-Food Materials, College of Medical and Life Sciences, Silla University)
  • 발행 : 2008.11.30
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⟨ 이전 논문 다음 논문 ⟩

초록

키틴과 그 탈아세틸화된 형태인 키토산은 지구 상에 가장 풍부하게 존재하는 바이오매스의 하나이다. 키틴과 키토산은 항균활성, 면역증강, 중금속 흡착 등 다양한 생리활성을 보이고 있으며 식품, 의약품, 환경산업 등에서 다양하게 응용되고 있다. 이러한 키틴/키토산을 가수분해하는 효소들과 그 3차구조, 유전자들이 세균, 고세균, 진핵생물등 모든 생물종에서 보고되어 왔다. 탄수화물을 가수분해하는 효소들은 그 아미노산 서열에 따라 CAZy (Carbohydrate Active Enzymes) 데이터베이스에 분류되었는데 흥미롭게도 최근까지 키틴가수분해효소와 키토산가수분해효소들은 14개의 glycosyl hydrolase (GH) family들로 분류되어 있다(GH2, GH5, GH7, GH8, GH18, GH19, GH20, GH46, GH48, GH73, GH75, GH80, GH84, GH85). 본 총설에서는 새로운 유전자원를 찾기위한 한 방편으로서 최근에 새롭게 분류된 glycosyl hydrolase family의 분류법에 따라 각각의 GH family에 속하는 키틴/키토산가수분해효소의 종류 및 구조, 그리고 그 효소적 특징에 대하여 논하고자 한다.

Chitin and chitosan, which is deacetylated form of chitin, are one of the most abundant biomass on the earth. They showed various biological activities including antimicrobial activity, heavy metal chelating, immune system activation, and have very diverse applications in food, pharmaceutical, medicinal, and environmental industry. There have been reported many chitin/chitosan-hydrolyzing enzymes, their structures and genes from three domains, archaea, bacteria, and eukarya. Carbohydrate hydrolyzing enzymes are classified in CAZy (Carbohydrate Active Enzymes) database according to their amino acid sequence similarity. Interestingly, chitinases and chitosanases are classified in various glycosyl hydrolase(GH) families, GH2, GH5, GH7, GH8, GH18, GH19, GH20, GH46, GH48, GH73, GH75, GH80, GH84, and GH85. Here, we review characteristics and structures of chitin/chitosan hydrolyzing enzymes according to glycosyl hydrolase families in order to provide information about gene mining.

키워드

참고문헌

  1. Anas, A., S. Paul, N. S. Jayaprakash, R. Philip and I. S. Bright Singh. 2005. Antimicrobial activity of chitosan against vibrios from freshwater prawn Macrobrachium rosenbergii larval rearing systems. Dis. Aquat. Organ. 67, 177-179. https://doi.org/10.3354/dao067177
  2. Beintema, J. J. 1994. Structural features of plant chitinases and chitin-binding proteins. FEBS Lett. 350, 159-163. https://doi.org/10.1016/0014-5793(94)00753-5
  3. Brameld, K. A. and W. A. Goddard, 3rd. 1998. The role of enzyme distortion in the single displacement mechanism of family 19 chitinases. Proc. Natl. Acad. Sci. U.S.A. 95, 4276-4281. https://doi.org/10.1073/pnas.95.8.4276
  4. Nucleic Acids Res.Bueno, A., C. R. Vazquez de Aldana, J. Correa and F. del Rey. 1990. Nucleotide sequence of a 1,3-1,4-beta-glucanase-encoding gene in Bacillus circulans WL-12. Nucleic Acids Res. 18, 4248. https://doi.org/10.1093/nar/18.14.4248
  5. Cao, Z. and Y. Sun. 2008. Chitosan-based rechargeable long-term antimicrobial and biofilm-controlling systems. J. Biomed. Mater. Res. A.(epub ahead of print).
  6. Cardenas, G., P. Orlando and T. Edelio. 2001. Synthesis and applications of chitosan mercaptanes as heavy metal retention agent. Int. J. Biol. Macromol. 28, 167-174. https://doi.org/10.1016/S0141-8130(00)00156-2
  7. Chen, Y. Y., C. Y. Cheng, T. L. Haung and Y. K. Li. 2005. A chitosanase from Paecilomyces lilacinus with binding affinity for specific chito-oligosaccharides. Biotechnol. Appl. Biochem. 41, 145-150. https://doi.org/10.1042/BA20040041
  8. Cheng, C. Y., C. H. Chang, Y. J. Wu and Y. K. Li. 2006. Exploration of glycosyl hydrolase family 75, a chitosanase from Aspergillus fumigatus. J. Biol. Chem. 281, 3137-3144. https://doi.org/10.1074/jbc.M512506200
  9. Choi, Y. J., E. J. Kim, Z. Piao, Y. C. Yun and Y. C. Shin. 2004. Purification and characterization of chitosanase from Bacillus sp. strain KCTC 0377BP and its application for the production of chitosan oligosaccharides. Appl. Environ. Microbiol. 70, 4522-4531. https://doi.org/10.1128/AEM.70.8.4522-4531.2004
  10. Cote, N., A. Fleury, E. Dumont-Blanchette, T. Fukamizo, M. Mitsutomi and R. Brzezinski. 2006. Two exo-$\beta$-D-glucosaminidases/exochitosanases from actinomycetes define a new subfamily within family 2 of glycoside hydrolases. Biochem. J. 394, 675-686. https://doi.org/10.1042/BJ20051436
  11. Dahiya, N., R. Tewari and G. S. Hoondal. 2006. Biotechnological aspects of chitinolytic enzymes, a review. Appl. Microbiol. Biotechnol. 71, 773-782. https://doi.org/10.1007/s00253-005-0183-7
  12. Eckert, C., S. Magnet and S. Mesnage. 2007. The Enterococcus hirae Mur-2 enzyme displays N-acetylglucosaminidase activity. FEBS Lett. 581, 693-696. https://doi.org/10.1016/j.febslet.2007.01.033
  13. Ekowati, C., P. Hariyadi, A. B. Witarto, J. K. Hwang and M. T. Suhartono. 2006. Biochemical Characteristics of Chitosanase From the Indonesian Bacillus licheniformis MB-2. Mol. Biotechnol. 33, 93-102. https://doi.org/10.1385/MB:33:2:93
  14. Elias, J. A., R. J. Homer, Q. Hamid and C. G. Lee. 2005. Chitinases and chitinase-like proteins in T(H)2 inflammation and asthma. J. Allergy Clin. Immunol. 116, 497-500. https://doi.org/10.1016/j.jaci.2005.06.028
  15. Feng, J., L. Zhao and Q. Yu. 2004. Receptor-mediated stimulatory effect of oligochitosan in macrophages. Biochem. Biophys. Res. Commun. 317, 414-420. https://doi.org/10.1016/j.bbrc.2004.03.048
  16. Fujita, K., K. Kobayashi, A. Iwamatsu, M. Takeuchi, H. Kumagai and K. Yamamoto. 2004. Molecular cloning of Mucor hiemalis endo-$\beta$-N-acetylglucosaminidase and some properties of the recombinant enzyme. Arch. Biochem. Biophys. 432, 41-49. https://doi.org/10.1016/j.abb.2004.09.013
  17. Fujita, K., K. Shimomura, K. Yamamoto, T. Yamashita and K. Suzuki. 2006. A chitinase structurally related to the glycoside hydrolase family 48 is indispensable for the hormonally induced diapause termination in a beetle. Biochem. Biophys. Res. Commun. 345, 502-507. https://doi.org/10.1016/j.bbrc.2006.04.126
  18. Fukamizo, T. 2000. Chitinolytic enzymes, catalysis, substrate binding, and their application. Curr. Protein Pept. Sci. 1, 105-124. https://doi.org/10.2174/1389203003381450
  19. Fukamizo, T. and R. Brzezinski. 1997. Chitosanase from Streptomyces sp. strain N174, a comparative review of its structure and function. Biochem. Cell Biol. 75, 687-696. https://doi.org/10.1139/bcb-75-6-687
  20. Fukamizo, T., A. Fleury, N. Cote, M. Mitsutomi and R. Brzezinski. 2006. Exo-$\beta$-D-glucosaminidase from Amycolatopsis orientalis, catalytic residues, sugar recognition specificity, kinetics, and synergism. Glycobiology 16, 1064-1072. https://doi.org/10.1093/glycob/cwl026
  21. Fukamizo, T., Y. Honda, S. Goto, I. Boucher and R. Brzezinski. 1995. Reaction mechanism of chitosanase from Streptomyces sp. N174. Biochem. J. 311, 377-383. https://doi.org/10.1042/bj3110377
  22. Hagglund, P., R. Matthiesen, F. Elortza, P. Hojrup, P. Roepstorff, O. N. Jensen and J. Bunkenborg. 2007. An enzymatic deglycosylation scheme enabling identification of core fucosylated N-glycans and O-glycosylation site mapping of human plasma proteins. J. Proteome Res. 6, 3021-3031. https://doi.org/10.1021/pr0700605
  23. Hahn, M., M. Hennig, B. Schlesier and W. Hohne. 2000. Structure of jack bean chitinase. Acta Crystallogr. D Biol. Crystallogr. 56, 1096-1099. https://doi.org/10.1107/S090744490000857X
  24. Hoell, I. A., B. Dalhus, E. B. Heggset, S. I. Aspmo and V. G. Eijsink. 2006. Crystal structure and enzymatic properties of a bacterial family 19 chitinase reveal differences from plant enzymes. FEBS J. 273, 4889-4900. https://doi.org/10.1111/j.1742-4658.2006.05487.x
  25. Honda, Y., T. Fukamizo, I. Boucher and R. Brzezinski. 1997. Substrate binding to the inactive mutants of Streptomyces sp. N174 chitosanase, indirect evaluation from the thermal unfolding experiments. FEBS Lett. 411, 346-350. https://doi.org/10.1016/S0014-5793(97)00726-6
  26. Huang, R. L., Y. L. Yin, G. Y. Wu, Y. G. Zhang, T. J. Li, L. L. Li, M. X. Li, Z. R. Tang, J. Zhang, B. Wang, J. H. He and X. Z. Nie. 2005. Effect of dietary oligochitosan supplementation on ileal digestibility of nutrients and performance in broilers. Poult Sci. 84, 1383-1388. https://doi.org/10.1093/ps/84.9.1383
  27. Ike, M., K. Isami, Y. Tanabe, M. Nogawa, W. Ogasawara, H. Okada and Y. Morikawa. 2006. Cloning and heterologous expression of the exo-$\beta$-D-glucosaminidase-encoding gene (gls93) from a filamentous fungus, Trichoderma reesei PC-3-7. Appl. Microbiol. Biotechnol. 72, 687-695. https://doi.org/10.1007/s00253-006-0320-y
  28. Jenkinson, H. F. and M. G. Shepherd. 1987. A mutant of Candida albicans deficient in $\beta$-N-acetylglucosaminidase (chitobiase). J. Gen. Microbiol. 133, 2097-2106.
  29. Kawase, T., A. Saito, T. Sato, R. Kanai, T. Fujii, N. Nikaidou, K. Miyashita and T. Watanabe. 2004. Distribution and phylogenetic analysis of family 19 chitinases in Actinobacteria. Appl. Environ. Microbiol. 70, 1135-1144. https://doi.org/10.1128/AEM.70.2.1135-1144.2004
  30. Kezuka, Y., M. Ohishi, Y. Itoh, J. Watanabe, M. Mitsutomi, T. Watanabe and T. Nonaka. 2006. Structural studies of a two-domain chitinase from Streptomyces griseus HUT6037. J. Mol. Biol. 358, 472-484. https://doi.org/10.1016/j.jmb.2006.02.013
  31. Lan, X., X. Zhang, R. Kodaira, Z. Zhou and M. Shimosaka. 2008. Gene cloning, expression, and characterization of a second $\beta$-N-acetylglucosaminidase from the chitinolytic bacterium Aeromonas hydrophila strain SUWA-9. Biosci. Biotechnol. Biochem. 72, 492-498. https://doi.org/10.1271/bbb.70573
  32. Langley, D. B., D. W. Harty, N. A. Jacques, N. Hunter, J. M. Guss and C. A. Collyer. 2008. Structure of N-acetyl-$\beta$-D-glucosaminidase(GcnA) from the endocarditis pathogen Streptococcus gordonii and its complex with the mechanism-based inhibitor NAG-thiazoline. J. Mol. Biol. 377, 104-116. https://doi.org/10.1016/j.jmb.2007.09.028
  33. Lee, H. S., D. S. Han, S. J. Choi, S. W. Choi, D. S. Kim, D. H. Bai and J. H. Yu. 2000. Purification, characterization, and primary structure of a chitinase from Pseudomonas sp. YHS-A2. Appl. Microbiol. Biotechnol. 54, 397-405. https://doi.org/10.1007/s002530000408
  34. Lee, H. S., J. S. Jang, S. K. Choi, D. W. Lee, E. J. Kim, H. C. Jung and J. G. Pan. 2007. Identification and expression of GH8 family chitosanases from several Bacillus thuringiensis subspecies. FEMS Microbiol. Lett. 277, 133-141. https://doi.org/10.1111/j.1574-6968.2007.00944.x
  35. Lemieux, M. J., B. L. Mark, M. M. Cherney, S. G. Withers, D. J. Mahuran and M. N. James. 2006. Crystallographic structure of human $\beta$-hexosaminidase A, interpretation of Tay-Sachs mutations and loss of GM2 ganglioside hydrolysis. J. Mol. Biol. 359, 913-929. https://doi.org/10.1016/j.jmb.2006.04.004
  36. Lonhienne, T., J. Zoidakis, C. E. Vorgias, G. Feller, C. Gerday and V. Bouriotis. 2001. Modular structure, local flexibility and cold-activity of a novel chitobiase from a psychrophilic Antarctic bacterium. J. Mol. Biol. 310, 291-297. https://doi.org/10.1006/jmbi.2001.4774
  37. Maeda, Y. and Y. Kimura. 2004. Antitumor effects of various low-molecular-weight chitosans are due to increased natural killer activity of intestinal intraepithelial lymphocytes in sarcoma 180-bearing mice. J. Nutr. 134, 945-950. https://doi.org/10.1093/jn/134.4.945
  38. Mark, B. L., D. J. Mahuran, M. M. Cherney, D. Zhao, S. Knapp and M. N. James. 2003. Crystal structure of human $\beta$-hexosaminidase B, understanding the molecular basis of Sandhoff and Tay-Sachs disease. J. Mol. Biol. 327, 1093-1109. https://doi.org/10.1016/S0022-2836(03)00216-X
  39. Mark, B. L., D. J. Vocadlo, S. Knapp, B. L. Triggs-Raine, S. G. Withers and M. N. James. 2001. Crystallographic evidence for substrate-assisted catalysis in a bacterial $\beta$-hexosaminidase. J. Biol. Chem. 276, 10330-10337. https://doi.org/10.1074/jbc.M011067200
  40. Masson, J. Y., F. Denis and R. Brzezinski. 1994. Primary sequence of the chitosanase from Streptomyces sp. strain N174 and comparison with other endoglycosidases. Gene 140, 103-107. https://doi.org/10.1016/0378-1119(94)90738-2
  41. Mayer, C., D. J. Vocadlo, M. Mah, K. Rupitz, D. Stoll, R. A. Warren and S. G. Withers. 2006. Characterization of a $\beta$-N-acetylhexosaminidase and a $\beta$-N-acetylglucosaminidase/$\beta$-glucosidase from Cellulomonas fimi. FEBS J. 273, 2929-2941. https://doi.org/10.1111/j.1742-4658.2006.05308.x
  42. Nogawa, M., H. Takahashi, A. Kashiwagi, K. Ohshima, H. Okada and Y. Morikawa. 1998. Purification and character ization of exo-$\beta$-d-glucosaminidase from a cellulolytic fungus, Trichoderma reesei PC-3-7. Appl. Environ. Microbiol. 64, 890-895.
  43. Ohno, T., S. Armand, T. Hata, N. Nikaidou, B. Henrissat, M. Mitsutomi and T. Watanabe. 1996. A modular family 19 chitinase found in the prokaryotic organism Streptomyces griseus HUT 6037. J. Bacteriol. 178, 5065-5070. https://doi.org/10.1128/jb.178.17.5065-5070.1996
  44. Pedraza-Reyes, M. and F. Gutierrez-Corona. 1997. The bifunctional enzyme chitosanase-cellulase produced by the gram-negative microorganism Myxobacter sp. AL-1 is highly similar to Bacillus subtilis endoglucanases. Arch. Microbiol. 168, 321-327. https://doi.org/10.1007/s002030050505
  45. Prag, G., Y. Papanikolau, G. Tavlas, C. E. Vorgias, K. Petratos and A. B. Oppenheim. 2000. Structures of chitobiase mutants complexed with the substrate Di-N-acetyld-glucosamine, the catalytic role of the conserved acidic pair, aspartate 539 and glutamate 540. J. Mol. Biol. 300, 611-617. https://doi.org/10.1006/jmbi.2000.3906
  46. Rao, F. V., H. C. Dorfmueller, F. Villa, M. Allwood, I. M. Eggleston and D. M. van Aalten. 2006. Structural insights into the mechanism and inhibition of eukaryotic O-GlcNAc hydrolysis. EMBO J. 25, 1569-1578. https://doi.org/10.1038/sj.emboj.7601026
  47. Rao, V., T. Cui, C. Guan and P. Van Roey. 1999. Mutations of endo-$\beta$-N-acetylglucosaminidase H active site residueAs sp130 anG glu132, activities and conformations. Protein Sci. 8, 2338-2346. https://doi.org/10.1110/ps.8.11.2338
  48. Rashid, M. H., M. Mori and J. Sekiguchi. 1995. Glucosaminidase of Bacillus subtilis, cloning, regulation, primary structure and biochemical characterization. Microbiology 141, 2391-2404. https://doi.org/10.1099/13500872-141-10-2391
  49. Reese, T. A., H. E. Liang, A. M. Tager, A. D. Luster, N. Van Rooijen, D. Voehringer and R. M. Locksley. 2007. Chitin induces accumulation in tissue of innate immune cells associated with allergy. Nature 447, 92-96. https://doi.org/10.1038/nature05746
  50. Renkema, G. H., R. G. Boot, A. O. Muijsers, W. E. Donker-Koopman and J. M. Aerts. 1995. Purification and characterization of human chitotriosidase, a novel member of the chitinase family of proteins. J. Biol. Chem. 270, 2198-2202. https://doi.org/10.1074/jbc.270.5.2198
  51. Saito, J., A. Kita, Y. Higuchi, Y. Nagata, A. Ando and K. Miki. 1999. Crystal structure of chitosanase from Bacillus circulans MH-K1 at 1.6-A resolution and its substrate recognition mechanism. J. Biol. Chem. 274, 30818-30825. https://doi.org/10.1074/jbc.274.43.30818
  52. Sasaki, C., A. Yokoyama, Y. Itoh, M. Hashimoto, T. Watanabe and T. Fukamizo. 2002. Comparative study of the reaction mechanism of family 18 chitinases from plants and microbes. J. Biochem. 131, 557-564. https://doi.org/10.1093/oxfordjournals.jbchem.a003134
  53. Shikhman, A. R., K. Kuhn, N. Alaaeddine and M. Lotz. 2001. N-acetylglucosamine prevents IL-1 $\beta$-mediated activation of human chondrocytes. J. Immunol. 166, 5155-5160. https://doi.org/10.4049/jimmunol.166.8.5155
  54. Shimosaka, M., Y. Fukumori, X. Y. Zhang, N. J. He, R. Kodaira and M. Okazaki. 2000. Molecular cloning and characterization of a chitosanase from the chitosanolytic bacterium Burkholderia gladioli strain CHB101. Appl. Microbiol. Biotechnol. 54, 354-360. https://doi.org/10.1007/s002530000388
  55. Song, H. K. and S. W. Suh. 1996. Refined structure of the chitinase from barley seeds at 2.0 a resolution. Acta Crystallogr. D Biol. Crystallogr. 52, 289-298. https://doi.org/10.1107/S0907444995009061
  56. Steen, A., G. Buist, G. J. Horsburgh, G. Venema, O. P. Kuipers, S. J. Foster and J. Kok. 2005. AcmA of Lactococcus lactis is an N-acetylglucosaminidase with an optimal number of LysM domains for proper functioning. FEBS J. 272, 2854-2868. https://doi.org/10.1111/j.1742-4658.2005.04706.x
  57. Synowiecki, J. and N. A. Al-Khateeb. 2003. Production, properties, and some new applications of chitin and its derivatives. Crit. Rev. Food Sci. Nutr. 43, 145-171. https://doi.org/10.1080/10408690390826473
  58. Takegawa, K., B. Mikami, S. Iwahara, Y. Morita, K. Yamamoto and T. Tochikura. 1991. Complete amino acid sequence of endo-$\beta$-N-acetylglucosaminidase from Flavobacterium sp. Eur. J. Biochem. 202, 175-180. https://doi.org/10.1111/j.1432-1033.1991.tb16359.x
  59. Tanabe, T., K. Morinaga, T. Fukamizo and M. Mitsutomi. 2003. Novel chitosanase from Streptomyces griseus HUT 6037 with transglycosylation activity. Biosci. Biotechnol. Biochem. 67, 354-364. https://doi.org/10.1271/bbb.67.354
  60. Tanaka, T., S. Fujiwara, S. Nishikori, T. Fukui, M. Takagi and T. Imanaka. 1999. A unique chitinase with dual active sites and triple substrate binding sites from the hyperthermophilic archaeon Pyrococcus kodakaraensis KOD1. Appl. Environ. Microbiol. 65, 5338-5344.
  61. Tarentino, A. L., G. Quinones, L. M. Changchien and T. H. Plummer, Jr. 1993. Multiple endoglycosidase F activities expressed by Flavobacterium meningosepticum endoglycosidases F2 and F3. Molecular cloning, primary sequence, and enzyme expression. J. Biol. Chem. 268, 9702-9708.
  62. Tews, I., R. Vincentelli and C. E. Vorgias. 1996. N-Acetylglucosaminidase (chitobiase) from Serratia marcescens, gene sequence, and protein production and purification in Escherichia coli. Gene 170, 63-67. https://doi.org/10.1016/0378-1119(95)00848-9
  63. Toratani, T., T. Shoji, T. Ikehara, K. Suzuki and T. Watanabe. 2008. The importance of chitobiase and N-acetylglucosamine (GlcNAc) uptake in N,N'-diacetylchitobiose [(GlcNAc)2] utilization by Serratia marcescens 2, 170. Microbiology 154, 1326-1332. https://doi.org/10.1099/mic.0.2007/016246-0
  64. Tsujibo, H., K. Fujimoto, H. Tanno, K. Miyamoto, C. Imada, Y. Okami and Y. Inamori. 1994. Gene sequence, purification and characterization of N-acetyl-$\beta$-glucosaminidase from a marine bacterium, Alteromonas sp. strain O-7. Gene 146, 111-115. https://doi.org/10.1016/0378-1119(94)90843-5
  65. Ubhayasekera, W., C. M. Tang, S. W. Ho, G. Berglund, T. Bergfors, M. L. Chye and S. L. Mowbray. 2007. Crystal structures of a family 19 chitinase from Brassica juncea show flexibility of binding cleft loops. FEBS J. 274, 3695-3703. https://doi.org/10.1111/j.1742-4658.2007.05906.x
  66. van Blitterswijk, W. J., J. C. van de Nes and P. I. Wuisman. 2003. Glucosamine and chondroitin sulfate supplementation to treat symptomatic disc degeneration, biochemical rationale and case report. BMC Complement Altern. Med. 3, 2. https://doi.org/10.1186/1472-6882-3-2
  67. Wang, S. L., T. Y. Lin, Y. H. Yen, H. F. Liao and Y. J. Chen. 2006. Bioconversion of shellfish chitin wastes for the production of Bacillus subtilis W-118 chitinase. Carbohydr. Res. 341, 2507-2515. https://doi.org/10.1016/j.carres.2006.06.027
  68. Yokoi, K. J., K. Sugahara, A. Iguchi, G. Nishitani, M. Ikeda, T. Shimada, N. Inagaki, A. Yamakawa, A. Taketo and K. Kodaira. 2008. Molecular properties of the putative autolysin Atl (WM) encoded by Staphylococcus warneri M, mutational and biochemical analyses of the amidase and glucosaminidase domains. Gene 416, 66-76. https://doi.org/10.1016/j.gene.2008.03.004
  69. Yun, C., D. Amakata, Y. Matsuo, H. Matsuda and M. Kawamukai. 2005. New chitosan-degrading strains that produce chitosanases similar to ChoA of Mitsuaria chitosanitabida. Appl. Environ. Microbiol. 71, 5138-5144. https://doi.org/10.1128/AEM.71.9.5138-5144.2005
  70. Zamani, A., L. Edebo, B. Sjostrom and M. J. Taherzadeh. 2007. Extraction and precipitation of chitosan from cell wall of zygomycetes fungi by dilute sulfuric acid. Biomacromolecules 8, 3786-3790. https://doi.org/10.1021/bm700701w
  71. Zverlov, V., S. Mahr, K. Riedel and K. Bronnenmeier. 1998. Properties and gene structure of a bifunctional cellulolytic enzyme (CelA) from the extreme thermophile 'Anaerocellum thermophilum' with separate glycosyl hydrolase family 9 and 48 catalytic domains. Microbiology 144, 457-465. https://doi.org/10.1099/00221287-144-2-457