Lower concentration of glucose was often obtained from enzymatic hydrolysis process of agricultural residue due to complexity of the biomass structure and properties. High substrate load feed into the hydrolysis system might solve this problem but has several other drawbacks such as low rate of reaction. In the present study, we have attempted to enhance glucose recovery from agricultural waste, namely, “sago hampas,” through three cycles of enzymatic hydrolysis process. The substrate load at 7% (w/v) was seen to be suitable for the hydrolysis process with respect to the gelatinization reaction as well as sufficient mixture of the suspension for saccharification process. However, this study was focused on hydrolyzing starch of sago hampas, and thus to enhance concentration of glucose from 7% substrate load would be impossible. Thus, an alternative method termed as cycles I, II, and III which involved reusing the hydrolysate for subsequent enzymatic hydrolysis process was introduced. Greater improvement of glucose concentration (138.45 g/L) and better conversion yield (52.72%) were achieved with the completion of three cycles of hydrolysis. In comparison, cycle I and cycle II had glucose concentration of 27.79 g/L and 73.00 g/L, respectively. The glucose obtained was subsequently tested as substrate for bioethanol production using commercial baker's yeast. The fermentation process produced 40.30 g/L of ethanol after 16 h, which was equivalent to 93.29% of theoretical yield based on total glucose existing in fermentation media.

An air-cathode MFC-adsorption hybrid system, made from earthen pot was designed and tested for simultaneous wastewater treatment and energy recovery. Such design had demonstrated superior characteristics of low internal resistance (29.3Ω) and favor to low-cost, efficient wastewater treatment and power generation (55mW/m(3)) with average current of 2.13±0.4mA. The performance between MFC-adsorption hybrid system was compared to the standalone adsorption system and results had demonstrated great pollutants removals of the integrated system especially for chemical oxygen demand (COD), biochemical oxygen demand (BOD3), total organic carbon (TOC), total volatile solids (TVS), ammoniacal nitrogen (NH3-N) and total nitrogen (TN) because such system combines the advantages of each individual unit. Besides the typical biological and electrochemical processes that happened in an MFC system, an additional physicochemical process from the activated carbon took place simultaneously in the MFC-adsorption hybrid system which would further improved on the wastewater quality.

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A B S T R A C TA cost effective single-chamber microbial fuel cell (MFC) integrated with adsorption system was tested under different operating temperatures to observe pH profiles, organics, solids, nutrients, color and turbidity removal and power density generation. The optimum operating temperature range was found to be $25-35 C with majority of the removals achieved at $35 C. Maximum power density recorded was 74 AE 6 mW/m 3 with coulombic efficiency (CE) of 10.65 AE 0.5% when operated at 35 C. Present studies had successfully demonstrated the effectiveness of a hybrid system in removing various types of pollutants in POME at optimum temperature and able to fulfill the stringent effluent discharge limit. Chemical oxygen demand (COD), total solids (TS) and turbidity removals increase linearly with temperatures with removal efficiency of 0.5889% C À1 , 1.0754% C À1 and 0.7761% C À1, respectively. The temperature coefficient (Q 10 ) is found to be 1.06, 1.45 and 1.09, respectively. Besides, MFC-adsorption hybrid system had demonstrated superior stability over a wide range of operating temperatures in terms of COD removal as compared to the non-integrated MFC system.

Previous works on the conversion of sago starch and sago hampas into sago sugar, production of cellobiose from sago fronds, and the current studies on the health benefits from consumption of brown sago sugar are presented in this paper. Hydrolysis of sago starch into sugar generates total (100%) recovery, containing glucose (94%), maltose, and other impurities at 3% each. Purification of the brown sago sugar is achieved using powdered activated charcoal to remove all impurities and color. Drying of the purified and concentrated white sago sugar is best performed in an oven (minimum 60 °C), producing high (100%) yield of sugar crystals after several days. Analysis of sweetness revealed that the sago sugar is as sweet as 50% glucose. Brown sago sugar is preferable to white sago sugar due to the presence of antioxidant, analyzed based on total phenolic content (TPC) at 300 mg/kg sugar. Some residual of the TPC can be detected even after purification of the brown sugar. Sago sugar is also obtainable through enzymatic hydrolysis of physically treated sago hampas, generating substantial amount of sugars (70% w/w). Current research also reveals the feasibility of producing cellobiose (approx. 12% w/w) from fresh sago frond, a type of pharmaceutical sugar which commands a higher price than glucose. It is obvious that sago palm has tremendous potential to be adopted as the new source of sugars to replace cane sugar.