ECOLOGICAL STUDIES ON TILE SYMBIOSIS OF TER ITOMYCES ...

7.4.1 INTRODUCTION
7.4 CELLULOSE DWJUDATION
Plant tissue contains from 15-64% cellulose (Table 7-3-30-
Cellulose In wood Its very resistant to bacterial attack largely due to
the presence of lignin* The cellulose of wood Ix a linear polymer of
d-glucose units linked by 1.4-jl-glucosidic bondsj In the form of long
linear molecules In a crystalline lattice bound laterally by hydrogen
bonds between hydroxyl groups (Cowling 19619 Swift et al- 1979)o
Cellulose breakdown requires at JeA t three different types of extra
cellular enzymes (Swift 1977)o Cl acts on crystalline cellulose,
pushing tho, polymer chains apart physically and creating free chain
encts,,, C. In a ccuplex of enzymes hydrolysing the P194-olucosidic bonds
in the cellulose volecule* Those produce celloblose on which colloblase,
or P-glycosidases acts to produce glucose, Cellujolytic micro-orgmuUM
which grow on native cellulose produce all the enzymes*
Cellulases, are produced by symbiotic Intestinal flagellate protozoa
In lower termiteaq and probably by bacteria In some higher termites
(Dreznak 1970- Potts and Hewitt (1973)
showed Trinervitermes
trinervoldes p roduced Its own callulaneo Some higher termites way eat
wood which has already undergone decay. Heim (1977)
considered that
Terml&ýeg, did not decompose cellulose. The cellulose decomposition
abilities -of cultures of Tormitgnces associated with different termite
species were investigated here by the use of cellophan4i films dyed with
332*
lkswwl Brilliant Blue R dye* Thin dye Is bound to the cellulose molecule
and released quantitatively In projx)rtlon to glucose (Moores Banset WO
Swift 1979)a