ISOLATION OF CELLULOLYTIC CHRYSONILIA SITOPHILA FROM TRIBOLIUM FERRUGINEUM SUMMARY

Chrysonilia sitophila was isolated from macerares of the insect Tribolium ferrugineum, found in rice hull from the State o[Goias, Brazil. It was found that C. sitophila ha~ celluloly tic activity, detennined by the method of Smith, using Petterson 's medium, wíth cellulose-azure as carbon source. In addition the essential aminoacid campositian was detennined in the [ungí. The possíble inte"e/ations between C. sitophi/a and T. fe"ugineum are discussed.


INTRODUCTION
Cellulosic materials which are 95% lignocellu-;. lose (1) represent the most abundant natural resource on earth (2). Generally these materials are recalcitran! and cause ecological problems when they are transformed by different processes. The biodegradation of these constituents, especially cellulose and lignin is extremely slow, and the majority of animals are unable to digest it. However, numerous microorganisms are able to degrade them either directly on in association with higher organisms, providing the hecessary degrading enzymes. These microorganisms, providing the necessary degrading enzymes. These microorganisms produce hydrolytic enzymes that act on polysacharides. Especially interesting is an enzimatic complex (3), due to its importance in the conversion of lignocellulosic materials to single cell protein for animal or to sugars, alcohols, adhesives and solvents ( 4). Rice hull and rice straw together with bagasse are the most abundant vegetal crops in Brazil (5). In a previous work an insect (6)  El hongo Chrysoni/io sitophi/a fue aislado a partir de macerados del insecto Tribolium ferrugineum, encontrado en muestras de cáscaras de a"oz procedentes del Estado de Goias, en Brasil.
Se discuten además las posibles inte"elaciones entre C sitophi/a y T. ferrugineum. and which feeds on a wíde varíety of products including all kinds of grains, flour, starchy materials, beans, peas and baking powder (7).
In this work the isolation and characterization of the fungus Chrysonilia sitophila is reported. The fungus was found in association with T. ferrugi· neum. Its cellulolytic activjty on various substrates was measured and its essential aminoacíd composítíon was determined.

MATERIAL ANO METHODS
Insect collection and identífícation. T. ferrugineum specimens were col!ected from samples of rice hull originally from Goias State (Brazil). The identification of the insect as Tribolium ferrugineum, Fabricius, (Ph. 1) Co!eoptera Tenebrionidae was done by Prof. H. Toro, Department of Enthomology, Universidad Católica de Valparaíso, Chile.
Culture media. The culture media used were Czapek Agar, Sabouraud Agar and Dextrose Agar for fungí and Nutrient Agar for bacteria. Besides the above 1 llollltion of cellulolytic Chry10nilitl dlophila -V. Campos et aL described media a culture medium was used whlch contained: Sodium nitrate 3 g., dipotassium phosphate 1 g., magnesium sulfate 0,5 g., potassium chloride 0,5 g. ferrous sulfate 0.01 g. per liter of destilled water; rice hull, cellulose and fJ.lter paper were uses as carbon sources. For determining cellulolytic activity Petterson's medium was used (9).
Sample preparation and microorganism isolation. T. ferrugineum specimens were desinfected by using concentrated HCI and then washed three times with sterile destilled water, macerated and innoculated in to Czapeck Agar, Sabouraud Dextrose Agar and Nutrient Agar for the isolation of the different microorganisms. Ten insects were macera· ted per sample, which was plated in triplicate .
Cellulolytic Activity test. The cellulolytic activity of the fungus was determined by th!! method of Smith (10), using Petterson's medium, which includes cellulose-azure (SIGMA) as carbon source. When the fungus degrades the cellulose-azure the dye Remazol brilliant blue R is liberated and can be measured qualitatively and thus, the cellulase activity can be determined. For a quantitative measurement of cellulose activity Petterson's medium without Agar and 2% of the cellulose-azure was used; 0.1 ml of fungal inoculum was added. The inoculum turbidity was equivalent to the value of tube N° 3 of the Mac-Farland standard. The absorbance at different times and at 595 nm was measured in a Microanal Spectrophotometer Model 382, after centrifuging the sample at 7 .000 rpm in a Exelse 2 centrifuge Model 205 N.
The cellulolytic complex was studied by cultivating the fungus in Petterson's medium without Agar with l.,. sacharose andO. 75.,. crystalline cellulose as inductor. The filtra te was analized at different times to measure the total cellulase activity on ftlter paper, endoglucanase activity on carboxymethylcellulose, cellobiohydrolase activity on microcrystalline cellulose, betaglucosidase activity on p-nitrophenylglucopiranoside and cellobiose, and hemicellulase activity on Xylan (11 -13).
Aminoacid composition. Aminoacid analysis of mycelial protein from fungi was perfom1ed in a Beckman 199 Cl Aminoacid Analyser. RESULTS AND DISCUSSION 1 In all microbial cultures obtained from macerated insects we found a fungus with irregular tufts at the margins of the petri dish. lnitially colourless, it became pinkish to orange at the second day of incubation at 28° C and showed more or Jess ascending conidiogenous hyphae, septate with lateral branches which forrn chains of conidia (Ph. 2). The fungus was identified as Chrysonilia sitophila (Mont) Von Arx , with a teleomorphic state that corresponds to Neurospora sitophila (Shear and Dodge) (14). ldentification was done by Dr. E. Piontelli from the Department of Mycology, Universidad de Valparaíso, Chlle. The habitat of this fungus is related to agricultural products, such as silages and meat, and to transportation and sto· rage rot of fruit. It has been reported in Europe, USA, Japan, Surinam and Indonesia (8).
Ocassionally , bacteria were isolated on Nutrient Agar but they were not considered in · thls work.
The cellulolytic activity of C. sitophila was determined in Petterson's medium and is shown in Ph. 4.; C. represents the control and X the fungus.   The data indicate that C. sitophilia has a cellulolytic activity (Ph. 3) which appears after 24 hrs. reaching a maximun at 84 hrs. in the logaritmic growth phase . It should be interesting to evaluate this activity in comparison with known cellulolytic fungi in order to study its possible industrial applications.
C. sitophila was isolated from macerated insects. This, indicates a permanent presence of the fungus in the insect . From the experimental data is difficult to say if C. sitophila is in symbiosis with T. ferrugineum. On other hand , it is possible that in this situation different microorganisms participate in symbiotic relation or in succesive chains as previously described in other systems; Total analysis of the intestinal microbiota is actually in progress in our laboratories. However, C. sitophila on the bases of its aminoacíd and cellulase contents, should play an important role in the feeding of T. ferrugineum , by providing essential aminoacids and carbon sources the latter from the biodegradation of lignocellulosic materials. In addition, the insect could play an important role in the dissemination of the fungus.