Ethanol and lactic acid production using sap squeezed from old oil palm trunks felled for replanting Akihiko Kosugi, 1 Ryohei Tanaka, 2 Kengo Magara, 2 Yoshinori Murata, 1 Takamitsu Arai, 1 Othman Sulaiman, 3 Rokiah Hashim, 3 Zubaidah Aimi Abdul Hamid, 3 Mohd Khairul Azri Yahya, 3 Mohd Nor Mohd Yusof, 4 Wan Asma Ibrahim, 4 and Yutaka Mori 1, ⁎ Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan, 1 Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan, 2 School of Industrial Technology, Universiti Sains Malaysia, 11800, Penang, Malaysia 3 and Forest Research Institute Malaysia (FRIM), Kepong, 52109 Selangor, Malaysia 4 Received 8 January 2010; accepted 2 March 2010 Available online 25 March 2010 Old oil palm trunks that had been felled for replanting were found to contain large quantities of high glucose content sap. Notably, the sap in the inner part of the trunk accounted for more than 80% of the whole trunk weight. The glucose concentration of the sap from the inner part was 85.2 g/L and decreased towards the outer part. Other sugars found in relatively low concentrations were sucrose, fructose, galactose, xylose, and rhamnose. In addition, oil palm sap was found to be rich in various kinds of amino acids, organic acids, minerals and vitamins. Based on these findings, we fermented the sap to produce ethanol using the sake brewing yeast strain, Saccharomyces cerevisiae Kyokai no.7. Ethanol was produced from the sap without the addition of nutrients, at a comparable rate and yield to the reference fermentation on YPD medium with glucose as a carbon source. Likewise, we produced lactic acid, a promising material for bio-plastics, poly-lactate, from the sap using the homolactic acid bacterium Lactobacillus lactis ATCC19435. We confirmed that sugars contained in the sap were readily converted to lactic acid with almost the same efficiency as the reference fermentation on MSR medium with glucose as a substrate. These results indicate that oil palm trunks felled for replanting are a significant resource for the production of fuel ethanol and lactic acid in palm oil-producing countries such as Malaysia and Indonesia. © 2010, The Society for Biotechnology, Japan. All rights reserved. [Key words: Oil palm; Trunk; Sap; Sugar; Ethanol production; Lactic acid production] Palm oil is the most produced plant oil, with a worldwide production of 4.3 million tons in 2008 (USDA statistics: PS&D online). The combined palm oil production in Malaysia and Indonesia accounts for approximately 88% of the worldwide production (USDA statistics: PS&D online). Since palm oil is cheaper than soybean oil or other oils, it is widely used for industrial purposes, such as in detergents and cosmetics, in addition to foods such as margarine and frying oil. Recently, palm oil has been considered as a material for the production of biodiesel (1,2) and bio-plastics (3,4). Oil palm (Elaeis guineensis) for palm oil production needs to be replanted at an interval of 20 to 25 years in order to maintain oil productivity. The plantation area in Malaysia and Indonesia in 2007 was 4,304,913 ha (5) and nearly 7 million ha (Janurianto, A., presentation at Indonesian Palm Oil Conference and Price Outlook 2010), respectively. Considering the replanting interval, 450,000 ha to 560,000 ha of the oil palm plantation area is expected to be replanted annually during the next 25 years. This means on average 64 million to 80 million old palm trees will be felled every year in the two countries, as approximately 142 oil palms are usually planted in one hectare (6). Consequently, the felled palm trunks can be regarded as one of the most important biomass resources in Malaysia and Indonesia. Unfortunately, the palm trunk structure is not strong enough for use as lumber, and thus, only the outer part of the trunk, which is relatively strong, is partially utilized for plywood manufacturing. In the plywood production process, the inner part is discarded in large amounts due to its extremely weak physical properties. Meanwhile, it is known that palm sugar and palm wine are produced from sap obtained by tapping the inflorescence of varieties of palm species, such as Arenga pinnata, Borassus flabellifer, Cocos nucifera, Nypa fruticans and oil palm (7). In order to utilize the old palm trunks felled for replanting, especially the inner part, we attempted to produce bioethanol and lactic acid, the material for bio-plastics, from felled trunks. We focused on sugars in the sap of the felled trunk and observed a large quantity of high glucose content sap in the trunk. Other components in the squeezed sap that may affect fermentation, namely, amino acids, organic acids, minerals and vitamins, were also assessed. The results Journal of Bioscience and Bioengineering VOL. 110 No. 3, 322 – 325, 2010 www.elsevier.com/locate/jbiosc ⁎ Corresponding author. Tel.: +81 298386307; fax: + 81 298386652. E-mail address: ymori@affrc.go.jp (Y. Mori). 1389-1723/$ - see front matter © 2010, The Society for Biotechnology, Japan. All rights reserved. doi:10.1016/j.jbiosc.2010.03.001