Assessment of agricultural waste-derived activated carbon in multiple applications.

To minimize waste production and reduce reliance on fossil fuels, agricultural waste such as rice straw has been actively used in biochemical production. In Taiwan, cellulosic waste has been used in anaerobic digestion for bioethanol production. This process produces a large amount of biomass-associated sludge that may become a serious environmental issue. Therefore, in this study, the anaerobic digestion sludge was recycled for the production of activated carbon via pyrolysis and activation by KOH. Surface characterization showed increased surface area and development of microporous structure upon activation. The FTIR image showed that high temperature activation eliminated most functional groups in the activated carbon, except for CO and C-O groups. The results showed that the activated carbon could be used for pollutant adsorbents such as molecular dyes (methylene blue: 217 mg g-1) and metal ions (copper: 169 mg g-1) from aqueous solution. In addition, the as-synthesized activated carbon can be used for CO2 capture and capacitor. Instead of focusing on one single application, we proposed that centralized production of activated carbon could be used in various applications, while further modification could be adopted depending on the need of its specific application.

Production of optically pure L(+)-lactic acid from waste plywood chips using an isolated thermotolerant Enterococcus faecalis SI at a pilot scale.

Utilization of renewable and low-cost lignocellulosic wastes has received major focus in industrial lactic acid production. The use of high solid loadings in biomass pretreatment potentially offers advantages over low solid loadings including higher lactic acid concentration with decreased production and capital costs. In this study, an isolated Enterococcus faecalis SI with optimal temperature 42 °C was used to produce optically pure L-lactic acid (> 99%) from enzyme-saccharified hydrolysates of acid-impregnated steam explosion (AISE)-treated plywood chips. The L-lactic acid production increased by 10% at 5 L scale compared to the similar fermentation scheme reported by Wee et al. The fermentation with a high solid loading of 20% and 35% (w/v) AISE-pretreated plywood chips had been successfully scaled up to process development unit scale (100 L) and pilot scale (9 m3), respectively. This is the first report of pilot-scale lignocellulosic lactic acid fermentation by E. faecalis with high lactic acid titer (nearly 92 g L-1) and yield (0.97 kg kg-1). Therefore, large-scale L-lactic acid production by E. faecalis SI shows the potential application for industries.