Abstract
Background
Malaysia is one of the largest producer of palm oil in the world with yearly yield of 19 000 million tonnes. With its large scale production of palm oil, Malaysia produces approximately 30 million tonnes of oil palm fronds (OPF) annually. The OPF as the main agricultural by-product in Malaysia have limited use especially as ruminant feed. It is due to its poor degradability which is caused by its high lignin content. One of the most promising method to increase the utilization of OPF as ruminant feed is via biological pretreatment. Previous study has shown an increase of 12% of ruminal degradability when pretreated using enzyme extract from white rot fungi
Results
The isolation of fungi yielded 11 fungi isolates. Upon the determination of their laccase, manganese peroxidase, lignin peroxidase, carboxylmethylcellulase, avicelase and xylanase, fungi F1, F2 and F4 were selected as the fungi with desirable enzyme activity. The fungi F1, F2 and F4 were then identified as Trichoderma harzianum MK027304, Trichoderma harzianum MK027305 and Fusarium solani MK027307 respectively. The highest total gas production was produced by OPF pretreated with enzyme extract from 15 days of solid state fermentation of Trichoderma harzianum MK027304. The highest methane was produced by OPF pretreated with enzyme extract from 30 days of solid state fermentation of Trichoderma harzianum MK027305. Highest volatile acid produced by OPF pretreated with enzyme extract from Fusarium solani MK027307 after 45 days of solid state fermentation. The apparent rumen degradable carbohydrate of the pretreatment also showed the highest increase over the unpretreated OPF with increment of 35.29%.
Conclusions
The pretreatment using enzyme extract from 45 days of solid state fermentation of Fusarium solani MK027307 have shown the ability to increase the degradability of OPF by 35.29%. This finding may decrease the feeding cost of ruminant by increasing the effectiveness of utilization of OPF.
Optimization of production of xylanases with low cellulases in Fusarium solani by means of a solid state fermentation using statistical experimental design
