RESUMO
A simple selective technique for the isolation of pure cellulolytic actinomycetes from natural sources was developed. Soil or manure samples are enriched in cellulolytic actinomycetes by thoroughly mixing 100g of the air dry sample with one gram of finely cut pieces of Whatman No. 1 filter paper and 10 ml of sterile water. Flasks are tightly plugged and wrapped in cellophane and kept for 7 days at [i] 28° for enrichment in mesophiles, [ii] 45 in thermotolerants and [iii] 55° in thermophiles, Triple-layer isolaltion plates are prepared in 15 cm wide sterile glass plates by pouring 5 mm in highs sterile water-agar layer [bottom layer], a sterile 15 cm in diameter Whatman No. I filter paper disc is gently placed [middle layer] over the solidified water-agar layer, a thim layer of 1-2 mm in hight, of Kosmatchev agar layer [top layer] is poured over the filter paper disc. Plates are seeded with one drop each of the suitable dilution of the enriched sample, followed by careful spreading using glass spreader. This method enables the pure selective isolation of mesophilic, thermnotolerant and thermophilic actinomycetes