DEVELOPMENT AND EVALUATION OF AN INOCULUM OF CELULOLYTIC BACTERIA

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In Colombia, the inappropriate management of solid waste continues generating serious problems related with soil, water, and air contamination. The objective of this research was to generate an inoculum of cellulolytic bacteria and evaluate its effectiveness for the transformation of organic solid waste. The study included soil samples from five native forests and five cereal producing farms and from three compost piles. From each sample a serial dilution until 10-4 was prepared. From each soil dilution test tubes containing liquid mineral medium and a strip of filter paper were inoculated. From the filter paper strips which showed zones of degradation the microorganisms were streaked, first on Agar Nutrient and then on solid mineral medium, supplemented with cellulose. The bacteria isolates obtained were evaluated for their cellulolytic capacity and those which showed the highest capacity tested for growth compatibility. In total, 20 isolates of cellulolytic bacteria were obtained, 19 from the native forests and one from a compost pile. Not all the isolates showed equal cellulolytic capacity, 5 of them did not show a halo of hydrolysis of cellulose and in the other 15 the amplitude of the halo varied between 0.1 and 0.7cm. Based on the cellulolytic capacity and compatibility for growth the isolates 1 (Bacillus sp.), 6 (Pseudomonas sp.), and 7 (Erwinia sp.) were selected to generate the inoculum. The inoculation of the compost piles with the selected cellulolytic bacteria or with the EM® and Agroplux® microorganisms did not produce effects statistically different to those naturally produced by the native microorganisms in the composting process.