Role of humic acid in improving the nutrient content and quality of fermented palm oil sludge

Abstract

Objective: An experiment was conducted to understand the effects of different microbes and doses of humic acid on the quality and nutrient content of Fermented Palm Oil Sludge (FPOS). Materials and Methods: The experiment was conducted using a 2×3 factorial Completely Randomized Design (CRD) with 3 replications. The first factor was two species of microbe, Neurospora sitophila and Neurospora crassa and the second was different doses of humic acid: (1) 100 ppm, (2) 200 ppm and (3) 300 ppm. The study parameters were the crude protein content, crude fiber content, nitrogen retention and digestible crude fiber content of FPOS. Results: The study parameters were more significantly affected by the interaction between the type of microbe and the dose of humic acid (p<0.01) than the humic acid dose alone. FPOS treated with Neurospora crassa and humic acid at 200 ppm showed better values for crude protein (23.74%), crude fiber (20.14%), crude lipid (2.70%), nitrogen retention (60.97%) and digestible crude fiber (55.63%) compared to FPOS treated with Neurospora sitophila. Conclusion: It is concluded that POS fermented with Neurospora crassa and 200 ppm humic acid provides the best food content and quality of FPOS.