The present study was concerned with bioethanol production from the pulverized Japanese cedar powder by simultaneous saccharification and fermentation (SSF). The pulverized Japanese cedar powder, which was treated with vibration grained named tandem-ring mill, could be efficiently converted into sugar in enzymatic saccarification. When SF was done using this pulverized powder and high-temperature fermentability yeast Schizosaccharomyces japonicus SS4-5 at 40 °C, ethanol production was inhibited. To improve the efficiency of ethanol production under high temperature condition, SS4-5 was subjected to UV irradiation. As the result of mutation, we obtained stable ethanol producing mutant, named SS4-5SP, under high temperature condition. When SSF was done using SS4-5SP at 40 °C, ethanol production and ethanol yield were 51.11 g/L and 81.81 %, respectively. High efficiency ethanol production can be achieved by SSF using SS4-5SP.

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To mitigate the energy crisis and the environmental damage from fossil fuels exploration to combustion, much attention has been focused on liquid biofuel production from algae to reduce CO₂ emission and dependence on petroleum. Among the existing algae-to-biofuels technologies, the hydrothermal treatment has been proposed as an attractive one since the produced bio-oil has lower oxygen content than pyrolysis, and the dewatering step of the feedstock is not necessary. However, much biomass residue will be produced associated with the oil extraction from algae, which should be discharged as wastes. Especially the aqueous fraction accounts for the major part of the products. In this study, a green microalgae obtained from TISTR (Thai Institute of Science and Technology Research), named No.8511, was processed under different hydrothermal conditions to investigate the properties of aqueous phase products in terms of the nutrient content. Hydrothermal treatment was conducted at different concentrations of algae (from 5 % to 30 %) and temperature ranges (from 210 °C to 290 °C). The major nutrition elements and trace metal elements in the aqueous phase were quantified and analyzed. The results showed that a considerable nutrition recovery in aqueous part is possible.

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For the biomass-to-liquid (BTL) process, pressurized gasification is an option in order to produce synthesis gas. Fixed bed gasification is promising as it results in relatively high conversion efficiencies as compared to other types of gasifiers on a smaller scale. Wood chips are adaptable feedstock for updraft fixed bed gasifiers. In considering whether to use waste materials or the use of powders for gasifiers, adaptability of the feedstock is a concern. For this study, a pressurized updraft fixed bed gasifier was chosen. The experimental setup comprised the gasifier, feedstock hopper, feeder, etc. inside a pressure vessel. Palm kernel shells (PKS) and wood pellets were used as feedstocks in this study. Although PKS is as adaptable feedstock as wood chips for updraft gasifiers, the adaptability of wood pellets, which are a kind of briquette biomass, has not been confirmed. As a result, good gasification was achieved with PKS, whereas problems such as channeling of the gas flow were caused using wood pellets. Such problems were reduced by lowering the bed height of the materials inside the gasifier, which increased the outlet gas temperature.

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Ethanol production from lignocellulosic biomass has attracted attention for utilization as an alternative fuel for internal combustion. Pretreatment is the first step in the conversion of lignocellulosic biomass to ethanol. Fermentation inhibitors generated by hydrothermal pre-treatment have an inhibitory influence on yeast growth and fermentation. Simultaneous saccharification and fermentation (SSF) is a promising, cost-effective method demonstrated in this study. We showed that yeast acquired thermotolerance in preculture at 35 °C and the thermotolerant yeast developed tolerance to 5-HMF by adding 5-HMF in preculture. Thus, we showed that Saccharomyces cerevisiae has the ability to tolerate stress caused by multiple factors including heat and inhibitors.

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