Abstract:

The purpose of this study is to isolate the cellulolytic filamentous fungi involved in the decomposition of water hyacinth to produce organic fertilizer. In this study, 13 different fungi were isolated and screened. Among them, isolate N.S8 showed the highest cellulase activity with the diameter of the clear zone of 35 mm. The isolate N.S8 was identified by sequencing the D1/D2 region of 28S rRNA coding gene. BLASTN analysis of sequenced 28S rRNA segment revealed that the isolate N.S8 is Aspergillus oryzae with identity value and E-value of 100% and 0.0, respectively. Additionally, culturing the isolate N.S8 in rice bran medium (pH 6.5) for 144 hours is the optimal method of improving cellulase activity. Moreover, the use of this isolate for composting water hyacinth created an organic fertilizer with nitrogen (N), phosphorus (P2O5), and potassium (K2O) contents of 3.35%, 0.43% and 0.74%, respectively after 45 days. Because of the high contents of nutrients, this organic fertilizer could solve the problems of fertilizer for crops with an efficiency being equivalent to that of chemical fertilizers which are known as one of the causes of soil degradation, environmental pollution and the negative effect on the quality of agricultural products.

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