This study evaluated the heating value derived from waste trees generated by thinning in Daejeon Metropolitan City. These trees are generated and stored in the forest without being handled separately after thinning. They can be used as a source of energy as they have a high heating value and, to avoid landslides during heavy rain, must be taken away from the forests properly. In 2014, statistical data of waste trees in Daejeon showed there were 2,152,352 m3 of conifers, 924,836 m3 of broad-leaved trees, and 662,914 m3 of mixed forest. The moisture content of conifers was 15.8%, that of broad-leaved trees was 11.5%, and that of mixed forest was 13.7%. The ash content of conifers was 7.0%, that of broadleaved trees was 4.0%, and that of mixed forest was 11.4%. All three types of tree satisfy the moisture and ash content criteria for fluff type Bio-SRF, i.e., 25% and 15%, respectively. Therefore, they are deemed sufficiently valuable as a source of energy. The heavy metal (Hg, Cd, Pb, As, Cr) content of conifers, broad-leaved trees and mixed forests each satisfies the heavy metal content criteria for Bio-SRF, i.e., 0.6 mg/kg, 5.0 mg/kg, 100 mg/kg, 5.0 mg/kg, and 70 mg/kg, respectively. The lower heating value of conifers was 5,070 kcal/kg, that of broad-leaved trees was 4,660 kcal/kg, and that of mixed forest was 4,820 kcal/kg. All three types of tree satisfy the lower heating value criteria for Bio-SRF, which is 3,000 kcal/kg, and, therefore, are deemed sufficiently valuable as a source of energy.

Background : The hypoglycemic effects of mulberry leaves extract were evaluated by comparing the abilities on glucose uptake in C2C12 myotubes and 3T3-L1 adipocyte. Glucose uptake of the extracts were identified to be enhanced by bio-conversion using cellulolytic enzyme like Viscozyme. Methods and Results : The mulberry (Morus alba L) leaves were extracted with 30% ethanol or hot water. The hypoglycemic compounds such as Moracin C and, Quercetin and 1-Deoxynojirimycin were identified from the extracts of mulberry leaves. The extracts were fermented using kinds of celluolytic enzymes, which were vicozyme, pectinase, β-glucosidase and xylanase, in order to increase the contents of hypoglycemic constituents in the extracts. The hypoglycemic effects of the fermented extracts were evaluated by comparing the abilities on glucose uptake in C2C12 myotubes and 3T3-L1 adipocyte. The extracts of mulberry leaves fermented with only Viscozyme were identified to increase glucose uptake in C2C12 myotubes and 3T3-L1 adipocyte by supplement of the concentration of 10 μM extracts, compared to insulin as control. However, bio-conversion effects by other enzymes were not shown in the treatments, suggesting hypoglycemic constituents in the extracts of mulberry leaves can be conversed to more active compounds by cellulolytic enzyme treatment like viscozyme. Conclusion : From the above results, we may suggest that the hypoglycemic constituents in mulberry leaves extracts can be conversed to more active compounds by cellulolytic enzymes.