Affinity purification and characterization of a biodegradable plastic-degrading enzyme from a yeast isolated from the la
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BIOTECHNOLOGICALLY RELEVANT ENZYMES AND PROTEINS
Affinity purification and characterization of a biodegradable plastic-degrading enzyme from a yeast isolated from the larval midgut of a stag beetle, Aegus laevicollis Ken Suzuki & Hironori Sakamoto & Yukiko Shinozaki & Jun Tabata & Takashi Watanabe & Atsushi Mochizuki & Motoo Koitabashi & Takeshi Fujii & Seiya Tsushima & Hiroko K. Kitamoto
Received: 4 September 2012 / Revised: 9 November 2012 / Accepted: 13 November 2012 # Springer-Verlag Berlin Heidelberg 2012
Abstract Two yeast strains, which have the ability to degrade biodegradable plastic films, were isolated from the larval midgut of a stag beetle, Aegus laevicollis. Both of them are most closely related to Cryptococcus magnus and could degrade biodegradable plastic (BP) films made of poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PBSA) effectively. A BP-degrading enzyme was purified from the culture broth of one of the isolated strains employing a newly developed affinity purification method based on the binding action of the enzyme to the substrate (emulsified PBSA) and its subsequent degradative action toward the substrate. Partial amino acid sequences of this enzyme suggested that it belongs to the cutinase family, and thus, the enzyme was named CmCut1. It has a molecular mass of 21 kDa and a degradative activity for emulsified PBSA which was significantly enhanced by the simultaneous presence of Ca2+ or Mg2+ at a concentration of about 2.5 mM. Its optimal pH was 7.5, and the optimal temperature was 40 °C. It showed a broad substrate specificity for p-nitrophenyl (pNP)-fatty acid esters ranging from pNP-acetate (C2) to pNP-stearate (C18) and films of PBSA, PBS, poly(ε-caprolactone), and poly(lactic acid).
Electronic supplementary material The online version of this article (doi:10.1007/s00253-012-4595-x) contains supplementary material, which is available to authorized users. K. Suzuki : H. Sakamoto : Y. Shinozaki : J. Tabata : T. Watanabe : A. Mochizuki : M. Koitabashi : T. Fujii : S. Tsushima : H. K. Kitamoto (*) National Institute for Agro-Environmental Sciences (NIAES), 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan e-mail: [email protected]
Keywords Biodegradable plastics . Aegus laevicollis . Midgut . Cryptococcus . Biodegradable plastic-degrading enzyme . Cutinase . Lipase
Introduction Driven by a growing demand for sustainable solutions to the problem of huge volume of plastic wastes, the commercial market of biodegradable plastics (BPs) has been expanding. Consequently, the European market for BPs is growing at an annual rate of roughly 20 %. The global production capacity of BPs is 56,500 tonnes in 2010 and is estimated to increase to 143,500 tonnes by 2015 (Lange 2011). Products that show vast growth rates include bags, catering products, agricultural mulching films, and food/beverage packaging materials. Each year after harvest, farmers have to gather and dispose used nondegradable plastic agricultural materials for recycle as industrial wastes. Unlike typic
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