Six anion-exchange resins with different properties were compared with respect to detoxification of a dilute-acid hydrolysate of spruce prior to ethanolic fermentation with Saccharomyces cerevisiae. The six resins encompassed strong and weak functional groups as well as styrene-, phenol-, and acrylic-based matrices. In an analytical experimental series, fractions from columns packed with the different resins were analyzed regarding pH, glucose, furfural, hydroxymethylfurfural, phenolic compounds, levulinic acid, acetic acid, formic acid, and sulfate. An initial adsorption of glucose occurred in the strong alkaline environment and led to glucose accumulation at a later stage. Acetic and levulinic acid passed through the column before formic acid, whereas sulfate had the strongest affinity. In a preparative experimental series, one fraction from each of six columns packed with the different resins was collected for assay of the fermentability and analysis of glucose, mannose, and fermentation inhibitors. The fractions collected from strong anion-exchange resins with styrene-based matrices displayed the best fermentability: a sevenfold enhancement of ethanol productivity compared with untreated hydrolysate. Fractions from a strong anion exchanger with acrylic-based matrix and a weak exchanger with phenol-based resin displayed an intermediate improvement in fermentability, a four- to fivefold increase in ethanol productivity. The fractions from two weak exchangers with styrene- and acrylic-based matrices displayed a twofold increase in ethanol productivity. Phenolic compounds were more efficiently removed by resins with styrene-and phenol-based matrices than by resins with acrylic-based matrices.

1 Several wastes from agro-industrial activities were mixed in different ratios to evaluate 2 the co-digestion process. Methane Yield (Y CH4 ), Specific Methanogenic Activity (SMA) 3 and a kinetic parameter (k 0 ) were determined. A second feeding was also performed to 4 examine the recovery of bacterial activity after exhaustion. 5

This study deals with the utilization of chicken feather waste as a substrate for anaerobic digestion and improving biogas production by degradation of the compact structure of the feather keratin. In order to increase the digestibility of the feather, different pretreatments were investigated, including thermal pretreatment at 120 °C for 10 min, enzymatic hydrolysis with an alkaline endopeptidase [0.53-2.66 mL/g volatile solids (VS) feathers] for 0, 2, or 24 h at 55 °C, as well as a combination of these pretreatments. The effects of the treatments were then evaluated by anaerobic batch digestion assays at 55 °C. The enzymatic pretreatment increased the methane yield to 0.40 Nm(3)/kg VS(added), which is 122 % improvement compared to the yield of the untreated feathers. The other treatment conditions were less effective, increasing the methane yield by 11-50 %. The long-term effects of anaerobic digestion of feathers were examined by co-digestion of the feather with organic fraction ...

ABSTRACT: Biogas and ethanol production from the residuals of a paper tube production factory were studied. The residuals were first pretreated, and then enzymatically hydrolyzed and fermented to ethanol or digested to biogas. The pre-treatment was carried out using concentrated phosphoric acid. Results showed that pre-treatment enhance the ethanol production compared to untreated material with 36%(from 0.14 to 0.19 g ethanol/g DM) using 15 FPU/g DM cellulase loading and by 33%(from 0.18 to 0.24 g ethanol/g DM) using ...

Summary Biological breakdown of organic municipal and industrial waste to biogas is already in use today. The technology is of outmost importance to attain the environmental goals that our society has set regarding to sustainable development. Of decisive economic ...