Sawdust in Ethiopia, despite of its abundance, is not being properly utilized. Pre-treatment has been found to be crucial step before enzymatic hydrolysis of lignocellulosic resources to obtain sugars from such resources. Various pre-treatment methods have been developed to facilitate these bio-conversion processes. This research was aimed at investigating the effects of the combined pretreatments of steam and mild NaOH with white rot fungi (WRF) on sawdust samples from Eucalyptus globulus and Cupressus lusitanica were investigated. The amounts of losses of lignin, cellulose and hemicellulose contents of the pretreated sawdust samples were measured. Samples of the pretreated sawdust samples were then subjected to the enzymes from the hydrolytic wood rot fungi for hydrolysis into fermentable sugars. It was observed that lignin, cellulose and hemicellulose losses of the two sawdust types increased with the increasing incubation days but lignin and hemicellulose were preferentially degraded than cellulose. Sugar yield obtained from the sawdust pretreated in the combination of NaOH with WRF and steam with WRF was significantly higher compared to the yield obtained from the NaOH and steam alone pretreated sawdust samples. Pretreatment by the combination of NaOH with the wood rot fungi significantly modified the recalcitrance nature of the sawdust samples than when steam combined with the fungi. Similarly, with increasing enzymatic hydrolysis periods, sugar yields significantly increased. Higher sugar yields were obtained from sawdust samples of E. globulus than C. lusitanica. The ligninolytic and cellulolytic fungi tested resulted in a notable sugar yields indicating the possible application of the wood rot fungi in sugar production from lignocellulosic sawdust wastes which could be used for different industrial applications.

Xylan is a second widely available polysaccharide in nature and can be enzymatically degraded for the production of sugars. The complete biodegradation of xylan needs synergistic action of different xylanolytic enzymes. In this research, potential xylanolytic activities of the wood rot basidiomycete fungi from Dagaga and Gambo forests were screened. Xylanases of the potential fungi were also quantitatively determined. Clear zones round the cultures on xylan supplemented agar media of isolate 011-1D (Trametes gibbosa) and 030-1D (Phellinus tremulae) were significantly wider than other isolates. The fungal isolates differently responded to the incubation days both in submerged and solid-state fermentations and most isolates gave higher xylanase yield in solid-state fermentation than in submerged fermentation. The enzymes were active and stable in the temperature range of 40 to 55oC and pH range of 4.0 to 6.0. Incubation temperature of 30 to 35oC and pH of 5.0 to 7.0 were found to be suitable for production of the xylanases from the fungal isolates. Among the supplemented carbon sources, carboxymethylcellulose, xylan and sucrose were found suitable for xylanase productions but most isolates differently responded to the nitrogen source supplementations. MgSO4, ZnSO4 and CaCl2 were also found to be suitable divalent metallic ions for the productions of the enzymes. The isolates could be used for hydrolysis lignocellulosic xylan to 5-carbon sugars by optimizing their growth conditions.

Biomass based traditional energy has been the main energy supply in Ethiopia. Efforts are being made to shift to modern bioenergy utilization but the level of contribution of modern bioenergy to the total energy supply of the country’s supply is not computed. In this synthesis we described the contribution of bioenergy to modern energy utilization in the country. Data used here was retrieved from the country’s official reports and published literatures. Access to modern cooking services in the country was particularly focused on and both biogas feedstock productivities and biogas processing efficiencies were calculated. Herfindahl Index (HI) was calculated to observe the change in the diversity of the total primary energy supply due to bioenergy in the country. Results indicated that only a few households, 10%, had access to modern bioenergy services. Less than 0.10% of households have a biogas digester. The HI values showed the low diversity of the energy supply and the very limited contribution of modern bioenergy. This synthesis indicated that the contribution of modern bioenergy to the energy supply of the country is very low. Very low difference was observed between Herfindahl Indexes with and without considering modern bioenergy in the total primary energy supply (TPES) of the country is also found to be insignificant. Results found indicated lower diversity of the energy supply of Ethiopia and very limited contribution of modern bioenergy to the diversity and security of the energy supply.