and Swietenia macrophylla were characterized and studied to find out and discover their potential utilization as suitable feedstocks for biofuel (ethanol) production. Characterization was done by evaluation of lignin, holocellulose and cellulose contents of woody biomass including the yield of reducing sugar (saccharification) after pretreated with alkaline (NaOH) at moderate temperature. Among 15 species of tropical forest wood biomass evaluated, our findings showed that M. gigantea was gave the highest yield of saccharified sugar (42.22%, weight of original wood dry basis) and also yield of theoretical ethanol (± 273 L/ton). We also found growth of M. gigantea was very fast to produce approximately 26,119 kg ha-1 dry biomass within 3 years. In general, the tropical wood biomass such as M. gigantea, A. moluccana, G. arborea, A. cadamba, and P. falcataria are suitable and potentially to be used as feedstocks for ethanol production due to their fast growing ability, availability and attractive chemical composition to produce high saccharified sugar and yield of ethanol.

Abstract. Ramadhan R, Phuwapraisirisan P, Amirta R, Darmawan MFB, Ul-Haq K, Kusuma IW, Suwito H, Abdulgani N, Mukhdlor A, Saparwadi. 2022. The potency of selected ethnomedicinal plants from East Kalimantan, Indonesia as antidiabetic agents and free-radical scavengers. Biodiversitas 23: 2225-2231. Ten ethnomedicinal plant extracts from East Kalimantan flora, traditionally used to treat blood sugar levels and other diabetes-related diseases, were examined in vitro for their antidiabetic and free radical scavenging activities by inhibiting rat alpha-glucosidase and several free radicals such as DPPH, ABTS, and Nitric oxide respectively. Out of the ten plant species investigated for their antidiabetic activity against maltase and sucrase rat alpha-glucosidase, three exhibited the strongest ?-glucosidaseinhibitory activity with maltose as a substrate, namely extracts of Garcinia nervosa, Syzygium caudatilimbum, and Shorea balangeran with IC50 values of 0.046; 0.037; 0.045 mg/mL. Meanwhile, quercetin as a positive control appeared to have a comparable IC50value. Furthermore, among the ten extracts, Syzygium caudatilimbum, Shorea balangeran, and Ixora javanica showed good inhibition against sucrase rat alpha-glucosidase. Moreover, the antioxidant test showed that the ten methanol extracts of plants from East Kalimantan have an antioxidant activity indicated by IC50values. The present study confirms that the ethnopharmacological use of selected plants from East Kalimantan might have potential as an antidiabetic and natural antioxidant.

Abstract. Adie MM, Krisnawati A. 2016. Identification of soybean genotypes adaptive and productive to acid soil . Optimalization of acidic land for soybean development can be performed through the provision of soybean variety adapted to low pH. A total of 13 soybean genotypes was identified for its performance on three acid soil sites in Lampung Province, Indonesia, from February to June 2015. Soybean variety adapted to acid soil (Tanggamus and Demas 1) were used as check varieties. The experiment was using Randomized Block Design, 15 traits and four replicates. The concentration of pH (H 2 O) in locations L1, L2 and L3 were 5.87, 5.04, and 4.73, respectively. The average yield in L1, L2 and L3 were 1.96 t/ha, 2.17 t/ha, and 1.92 t/ha, respectively. This showed that yield decrease as soil pH value decline. Genotype G4AB was consistently produced highest yield at pH 5.04 as well as at pH 4.73, hence the genotype G4AB was not only adaptive at low pH but also relatively productive. Based on yield in three locations, G4AB categorized as less stable. On the contrary, genotype G115H/Kaba//Kaba///Kaba-8-6 produced average yield of 2.23 t/ha, and categorized as stable in three sites of acid soil. Soybean genotype adaptive to acid soil was characterized by its ability to maintain the plant height, and followed by a high number of node per plant and pod per plant.

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Abstract. Yuliansyah. Haqiqi MT, Setiawan KA, Setiawan A, Saputra PD, Romadlon HSI, Mukhdlor A, Ramadhan R, Amirta R. 2022. Fast-growing native tree species to the secondary forest of East Kalimantan, Indonesia: Physicochemical properties of woody materials for bioelectricity feedstocks. Biodiversitas 23: 3379-3386. The conversion of woody biomass into electricity through a thermochemical process has recently attracted significant attention worldwide to promote green energy production. It provides a low-cost and straightforward operation promising for developing rural areas, especially with limited transportation access. In East Kalimantan Province, almost all remote areas are surrounded by forests with high tree species diversity, which is the potential to be utilized for sustainable feedstocks in electric power plants. This study pointed out the energy potential produced from woody biomass of selected fast-growing tree species native to East Kalimantan secondary tropical forest: Elaeocarpus ferrugineus (Jacq.) Steud., Ficus aurata (Miq.) Miq., Fordia splendidissima (Blume ex Miq.) Buijsen, Lindera lucida (Blume) Boerl., Mallotus paniculatus (Lam.) Mull. Arg. and Schima wallichii (DC). Their wood physicochemical properties were firstly investigated. Furthermore, each species' wood quality for solid energy purposes was presented as the fuel value index (FVI). The results revealed that the change from greenwood into wood chip effectively removed the moisture content, thus improving efficiency to achieve higher energy potency. Our findings showed that the highest energy potency was obtained from the wood chip of F. splendidissima (3.61 MWh/ton), followed by S. wallichii (2.98 MWh/ton). A similar pattern was also found in FVI determination showing that the wood chip of S. Splendidissima had the greatest value (8970). Therefore, we observed that the high quality of S. splendidissima compared to other selected fast-growing species indicates its high suitability for further large-scale crop plantation to supply wood chips for biomass-based electricity generation.