Abstracts

AGRICULTURAL BIODEGRADATION

113

Bioconversion of Sugar Cane and Citrus Vinasse by Four Aspergillus Species V.M.V. Vitali and C. Kiyan UNESP, SP. Brazil

The Aspergillus fungi have been the object of much study about agroindustrial effluent degradation due to the great variety of enzymes they present. A. niger, A. oryzae, A. japo- nicus and A. sulphureus were cultivated in sugar cane vinasse and A. niger and A. sulphureus in a citrus one diluted to 12.5% in sugar cane vinasse. To both were added 2.5% of molasses and incubated at (28 + 2) “C for 72 h. Our objective was to study the pollution charge reduction of the vinasse. In sugar cane vinasse A. niger presented a better performance in the reduction of total and organic solids with a result of about 40%, but the best COD reduction was 73.94% with A. sulphureus. In the citrus vinasse, which is a richer medium, the COD reduction was around 60% for both fungi.

Decolorization of Sugar Cane Molasses by Ligninolytic Cultures of Phanaerochaete crysosporium L.R. Durrant Facutad Engenharia de Alimentos, UNICAMP, Brazil

Molasses is a by-product of either the manufacture or relining of sugarcane. It is widely used in industry as a feed stock for fermentation processes, but the presence of highly colored substances in molasses, which are not degraded by conven- tional methods, can lead to environmental pollution. Here, the decolorization of molasses pigments by ligninolytic cultures of P. chrysosporium is demonstrated. Furthermore, the addition of molasses to the growth medium caused an increase in the production of lignin peroxidase. Decolorization of molasses pigments occurred simultaneously with the appearance of lignin peroxidase and the degree of decolorization was proportional to the activity of the enzyme. Conditions that did not allow the establishment of the ligninolytic phase of the fungus prevented color disappearance. Immobilization of the fungus in polyurethane foam allowed successive production of lignin peroxidase and decolorization of molasses pigments, offering the possibility of scaling-up the process.

Lactic Acid Production by Biodegradation of Agroindustrial Residues A.S. Oliveira, R.J.H.C. Gomez and M.C.O. Hauly Departamento Bioquimica, Universidade de Londrina, P.R., Brazil

Lactic acid has many uses in pharmaceutical, chemical and food industries. It is obtained from various raw materials by fermentative processes. However, bacteria of the genus Lacto- bacillus are usually very exigent in their nutritional require- ments. They need the correct proportion of carbon, nitrogen, minerals and vitamins in the culture medium. In view of their ready availability and high nutritional value, especially in carbohydrate and protein content, two industrial residues, whey and distillery yeast, were evaluated for their interactions with the aim of obtaining a low cost adequate culture medium for the promotion of the lactic fermentation by Lactobacillus curvatus. Good results, an average of 2.2g% of lactic acid,

were obtained using culture media containing the two agroin- dustrial residues. Lactic acid was determined spectro- photometrically.

Xylanase Production by the Basidiomycete Fungi Cyathus stercoreus, Len&us edodes and Schizophillum commune M.F.G. Petry and R.W.S.P. Thomas Agronomy Faculty, UFRGS, Porto Alegre. RS., Brazil

The fungi Cyathus stercoreus, Lentinus edodes and Schizo- phillum commune were assessed for their capacity to grow on mineral salts agar, using wheat bran as sole carbon source and pH values of 5 and 6. Results showed that mineral salts were not necessary for the growth of these fungi. In subsequent experiments, sterilized wheat bran (50% RH), pH 5.5, was inoculated with mycelial disks and statically incubated at 28 “C for 14 days. Xylanase activity was assayed using 3,5- dinitro-salicylic acid reagent with wheat spent xylan as substrate. S. commune produced 180 nkats of xylanase activity whilst C. stercoreus and L. edodes produced approximately 10 nkats. These results suggest that S. commune could be used for the production of xylanase or for improving the nutritional value of wheat bran.

Treatment of Waste Water from a Chicken Abbatoir by Purple Non-Sulphur Photosynthetic Bacteria) E.M. Silva and P.M. Lacava Departamento de Bioquimica, UNESP, Araraquara, S. Paulo, Brazil

The viability of treating waste waters from a chicken abattoir by using them as a culture medium for Rhodocyclus gezatinosus was studied. BOD and COD values were initially 470.0- 780.0 mg 02/1 and 1,100.0-l ,960.O mg 02/l, respectively. The pH was 7.3-8.9 and the ether-soluble fat content 0.83mg/l. The inoculum was isolated from the sedimentation tanks of the abattoir. Treatment was in one litre batch reactors and, as a pilot study, in vertical glass columns, 1.8 m x 16cm diame- ter. BOD, COD and pH were monitored at a temperature of 30 + 3°C and light intensity of 1,600 lux.

Toxicity Evaluation in a Biological Treatment System of Citrus Wastes A.R. Siviero”, I.R.C. Britob, D.F. De Angelisb, V.J.A. Oliveirab and V.J. Carraron “Sanitation Laboratory Civil Engineering, UNICAMP, Campi- nas, Brazil and bDepartment of Biochemistry and Microbiology, UNESP, Rio Clara, Brazil

The research was carried out at biological treatment station of a citrus industry in Sao Paulo state, Brazil. This station oper- ates with anaerobic and aerobic systems which are composed of three and two lagoons, respectively. The decrease of the organic matter in the lagoons was followed by the Chemical Oxygen Demand (COD). The sublethal toxicity assay was also analyzed with the microcrustaceous Daphnia similis. Composed samples were collected every 2 h during a period of 12 h in six different places of the station. The efficiency of the