CHITINOLYTIC ENZYMES IN THE RUMEN MICROBIAL ECOSYSTEM | HITINOLITIČNI ENCIMI V VAMPNEM MIKROBNEM EKOSISTEMU

anglais. Chitinolytic systems of rumen Clostridia (usually the most active rumen chitinolytic bacteria) and rumen anaerobic fungi were compared in the present study. The chitinolytic enzymes of tested Clostridia strains were represented mainly by extracellular exochitinases, N-acetylglucosaminidases, chitin deacetylases and chitosanases. Zymograms of exochitinases revealed that these enzymes were bound in complexes with MW higher than 100 kDa. Final products of chitin degradation were glucosamine, N-acetylglucosamine and chitin oligosaccharides. Fungal chitinases were represented mainly by extracellular endochitinases and chitin deacetylase in both mono- and polycentric fungi. The main activities in cellular fraction were chitosanase and endochitinase. There were no or low activity of N-acetylglucosaminidase activity in all fungal strains tested. In comparison with rumen chitinolytic bacteria there was lower production of exochitinases and no production of N-acetylglucosaminidase in rumen fungi.

slovène. Primerjali smo hitinolitične encimske sisteme vampnih predstavnikov rodu Clostridium (običajno najaktivnejše vampne hitinolitične bakterije) in anaerobnih vampnih gliv. Hitinolitične encime proučevanih klostridijev so večinsko predstavljale ekstracelularne eksohitinaze, N-acetilglukozaminidaze, hitinske deacetilaze in hitozanaze. Z eksohitinaznimi encimogrami smo ugotovili, da se ti encimi vežejo v komplekse z MW, večjimi od 100 kDa. Končni produkti razgradnje so bili glukozamin, N-acetilglukozamin in hitinski oligosaharidi. Tako pri mono kot pri policentričnih glivah pa predstavljajo glavne hitinaze predvsem ekstracelularne endohitinaze in hitinske deacetilaze. V celični frakciji je bila največja aktivnost posledica delovanja hitozanaz in endohitinaz. Pri vseh preiskanih sevih smo odkrili le nizko aktivnost (ali pa je spoh nismo zasledili) N-acetilglukozaminidaz. V primerjavi s klostridiji smo pri vampnih glivah odkrili nižjo raven nastajanja eksohitinaz in nič N-acetilglukozaminidaz.