Indonesian Institute of Sciences

About: Indonesian Institute of Sciences is a facility organization based out in Jakarta, Indonesia. It is known for research contribution in the topics: Population & Genus. The organization has 4795 authors who have published 10544 publications receiving 76990 citations. The organization is also known as: Indonesian Institute of Sciences Cibinong, Indonesia.

Optimization of Microwave-Assisted Oxalic Acid Pretreatment of Oil Palm Empty Fruit Bunch for Production of Fermentable Sugars

Abstract: Pretreatment is an important step in the conversion of biomass to bioethanol. In this study microwave-assisted oxalic acid (MOA) pretreatment was chosen to pretreat oil palm empty fruit bunch (OPEFB) to enhance enzymatic saccharification of the biomass. The objective of this study was to determine an optimum pretreatment condition for reducing sugar production, which could be further fermented by yeast to produce ethanol. Preliminary study was conducted to determine the range of duration of heating and temperature that will be used in the optimization by using response surface methodology (RSM). Central composite design (CCD) was used with three independent variables (duration of heating, temperature and acid concentration). Reducing sugar yield per initial biomass was used as a response variable. Preliminary study, that was conducted at 160, 170, 180, 190, and 200 °C for 5, 7.5, 10, 12.5, and 15 min, shows that pretreatment at temperature of 170–190 °C for 5–10 min produced higher reducing sugars than other conditions. Optimization using RSM shows that the optimum condition of MOA pretreatment of OPEFB was at 190 °C for 3 min with 1.1% oxalic acid, which resulted in as much as 34.60% reducing sugars after enzymatic saccharification. The pretreated OPEFB was then characterized and compared with untreated OPEFB. MOA pretreatment successfully removed 50.57% of lignin and 76.56% of hemicellulose from the OPEFB that were confirmed by a decrease or disappearance of the absorption bands of functional groups at 1339–1650 cm−1 and 1735 cm−1, respectively.

Vegetation analyses of Sebangau peat swamp forest, Central Kalimantan

Abstract: Mirmanto E (2010) Vegetation analyses of Sebangau peat swamp forest, Central Kalimantan. Biodiversitas 11: 82-88. The vegetation analysis study has been made in Sebangau peat-swamp forest, Central Kalimantan. Eight permanent plots of 50-m x 50-m were set-up distribute from close to the river with shallow peat-layer up to the inland with relatively deep peat-layer. Enumeration of trees (GBH > 15 cm) was conducted in all of 8 plots. Overall there are 133 species (taxa) were recorded within 8 plots belong to 34 families where Dipterocarpaceae, Clusiaceae, Myrtaceae and Sapotaceae were the most dominant family. Out of all species recorded, Combretocarpus rotundatus, Palaquium leiocarpum, Stemonurus scorpioides and Tristania whittiana were the most dominant species. Two community’s types namely Combretocarpus rotundatus-Shorea balangeran community and Palaquium leiocarpum-Eugenia densinervium communitywere recognized and they distributed in slightly different habitat condition. The sequence of these two communities’ shows significantly related to both distances to river and peat-depth. In addition there was indication the presence of habitat preference among tree species.Key words: vegetation, peat-swamp, community, Sebangau, Central Kalimantan

Accommodation space, relative sea level, and the archiving of paleo-earthquakes along subduction zones

Abstract: The spatial variability of Holocene relative sea-level (RSL) change influences the capacities of coastal environments to accommodate a sedimentary record of paleoenvironmental change. In this study we couch a specific investigation in more general terms in order to demonstrate the applicability of the relative sea-level history approach to paleoseismic investigations. Using subsidence stratigraphy, we trace the different modes of coastal sedimentation over the course of time in the eastern Indian Ocean where RSL change evolved from rapidly rising to static from 8000 yr ago to present. Initially, the coastal sites from the Aceh, Sumatra, coastal plain, which are subject to repeated great earthquakes and tsunamis, built up a sedimentary sequence in response to a RSL rise of 1.4 mm/yr. The sequence found at 2 sites 8 km apart contained 3 soils of a mangrove origin (Rhizophora, Bruguiera/Ceriops, Avicennia pollen, and/or intertidal foraminifera) buried by sudden submergence related to coseismic subsidence and 6 tsunami sands that contain pristine subtidal and planktic foraminifera. After 3800 cal yr B.P. (years before A.D. 1950), sea level stabilized and remained such to the present. The stable relative sea level reduced accommodation space in the late Holocene, suggesting that the continued aggradation of the coastal plain was a consequence of periodic coastal inundation by tsunamis.