The digestion of potato waste by ruminal microorganisms is presented in Fig 1. The results showed that the use of ruminal microorganisms has caused the digestion of most potato waste, so 79.78% of potato waste in 100 g PW treatment was digested, which had a significant difference with other levels (P < 0.05).
Rumen microorganisms have been successfully employed to digest a variety of lignocellulosic biomass, including agricultural residues, organic fraction of the municipal solid wastes and aquatic plants (Barnes and Keller, 2004; Hu and Yu, 2005; Yue et al., 2007).
Substrate concentration and pH are other two important factors governing the acidogenesis of wastes (Hwang et al., 2001; Sanchez et al., 2001; Hu et al., 2004).
The nutrient composition of potato waste was measured at the start and end of the experiment (Table 1). Adding ruminal microorganisms to potato waste caused a significant increase in cp content up to 17/95% (100g pw) compared to the control group (10/11%). The highest percentage of EE was observed in treatment 100 g PW (P < 0.05).
Research results showed the using of fungus (Fusarium moniliforme and Saccharomyces cerevisiae) for bioconversion sweet potato residue, enhanced the biomass yield and protein production (Aziz & Mohsen, 2002). The utilization of several chemical, physical and enzymatic treatments on different agricultural wastes were impressive increasing the microbial digestibility as well as in raising the product of a protein rich- biomass (1,8,9,12,14,16,18,25).
Aspergillus niger, Chaetomium globosum and Saccharomyces cerevisiae were used in singles and in combinations to ferment sorghum grains and sweet potato leaves. All the microbial treatments brought about significant increases (P