Comparative characterization of Macaranga species collected from secondary forests in East Kalimantan for biorefinery of unutilized fast growing wood

Abstract

Macaranga species collected from secondary forests in East Kalimantan for biorefinery of unutilized fast growing wood. Biodiversitas 17: 116-123. Wood species for industrial forest plantation has been selected to produce construction wood materials, boards and papers, and unutilized fast growing wood as a source for biofuel production has been out of the scope for selection. Macaranga Thouars (Euphorbiaceae) is widely distributed in the tropics and importance of the genus has been recognized due to its high level of growth rate and adaptability to constitute forest ecosystem. However, potency of the genus as a source for bioethanol production has not been systematically studied. We herein first report differential properties of six Macaranga wood species collected in East Kalimantan, Indonesia, as a raw feedstock for enzymatic saccharification for bioethanol production. Among the wood species examined, the highest sugar yield 48.6% (weight of original wood basis), which corresponds to 315 mL ethanol/kg biomass, was obtained with 5.0% NaOH at 160ºC for M. hypoleuca. Significant differences in the sensitivity to alkaline concentration and temperature have been found among the species. A high sugar yield, 40.4% was obtained for M. winkleri with a low alkaline concentration, 3.5% NaOH at 150ºC, while M. motleyana gave the sugar yield 12.8% under the same condition. M. motleyana required a set of the conditions with higher NaOH concentration 5.0% and temperatures over 160ºC. The harsh condition with 5.0% NaOH at 170ºC promoted delignification of all the species but M. hypoleuca decreased the saccharification yield by raising the temperature from 160ºC to 170ºC, probably due to decomposition of carbohydrate cores. This temperature-dependent negative effect was not observed with 3.5% NaOH for M. hypoleuca. These results indicate that differences in the balance between disintegration effects and excess degradation of carbohydrates are different among the species and the variation should be taken into account on screening. Thus, we found a wide range of diversity in the susceptibility to alkaline pretreatment in the genus Macaranga and selected the wood species giving high productivity of fermentable sugars.

Searching for potential wood biomass for green energy feedstock: A study in tropical swamp-peat forest of Kutai Kertanegara, Indonesia

“…Most of the information of energy plant species were reported from the lowland forest areas, such as Willow (Salix viminalis), Poplar (Populus trichocarpa),_ Black Locust (Robinia pseudoacacia), and also Acacia (Acacia melanoxylon) and Eucalyptus (Eucalyptus globulus) trees, commonly used in Denmark, Germany, Poland, Italy, New Zealand and other European countries (Sims et al 2001;Sims and Venturi 2004;Fiala and Bacenetti 2012;Dillen et al 2013;Ghaley and Porter 2014;Hauk et al 2014;Haverkamp and Musshoff 2014;Krzyzaniak et al 2015;Niemczyk et al 2018). Similar situation exists in Indonesia forest energy sector where very limited number of plant species, such as Calliandra calothyrsus, Glyricidia sepium, Macaranga hypoleuca and Vitex pinnata are known as the energy feedstock (Amirta et al 2016a;2016b). Therefore, in this paper, an attempt was made to find out the diversity, productivity and suitability of tree and woody shrub species in the swamp-peat forests of East Kalimantan, Indonesia which has the potential be used as high-quality feedstock for sustainable green energy production.…”

Short Communication: Diversity of plant species growing during fallow period of shifting cultivation and potential of its biomass for sustainable energy production in Mahakam Ulu, East Kalimantan, Indonesia

“…Macaranga was also reported as the pioneer plant species that usually grow sporadically on the gap of forest canopy, and disturbed areas after forest fire or opening area for the shifting cultivation (Slik et al 2003;Crepaldi et al 2016). Moreover, shrub and tree species such as Melastoma and Macaranga were also traditionally used by Dayak people and local farmers in East Kalimantan as the natural key plant species indicator to determine the end of the recovery period of forest land after ground fire or shifting cultivation activities (Amirta et al 2016b;Susanto et al 2016;Imang et al 2008). (Kiyono and Hastaniah 2005;Arung et al 2017;Goh et al 2017).…”

“…In the present study, M. pearsonii, M. hypoleuca and M. triloba were classified as species with low wood density (<0.4 g/cm 3 ). The lower wood density is related to fastgrowing ability of plant biomass species, thus affecting the cost of transport, storage and drying process (De Oleivera et al 2013;Amirta et al 2016aAmirta et al , 2016bAmirta et al , 2019.…”

Optimization Method for Bioethanol Production from Giant Cassava (<i>Manihot esculenta</i> var. Gajah) Originated from East Kalimantan

“…cassava [12], sweet potatoes [13], sago [6], sorghum, banana [14], iles-iles [15], and breadfruit [16]; rich in lignocellulose, e.g. sugarcane bagasse [17], coconut husk [18], macaranga wood [19], cassava peel [20], durian seed [21], and rice straw [22] are one of the raw materials for bioethanol generation. The raw material in the form of heteropolymer polysaccharides, e.g., seaweed [23][24] also can be used in the production of bioethanol.…”