Synergy between bio-based industry and the feed industry through biorefinery.

Processing biomass into multi-functional components can contribute to the increasing demand for raw materials for feed and bio-based non-food products. This contribution aims to demonstrate synergy between the bio-based industry and the feed industry through biorefinery of currently used feed ingredients. Illustrating the biorefinery concept, rapeseed was selected as a low priced feed ingredient based on market prices versus crude protein, crude fat and apparent ileal digestible lysine content. In addition it is already used as an alternative protein source in diets and can be cultivated in European climate zones. Furthermore, inclusion level of rapeseed meal in pig diet is limited because of its nutritionally active factors. A conceptual process was developed to improve rapeseeds nutritional value and producing other bio-based building blocks simultaneously. Based on the correlation between market prices of feed ingredients and its protein and fat content, the value of refined products was estimated. Finally, a sensitivity analysis, under two profit scenario, shows that the process is economically feasible. This study demonstrates that using biorefinery processes on feed ingredients can improve feed quality. In conjunction, it produces building blocks for a bio-based industry and creates synergy between bio-based and feed industry for more efficient use of biomass. © 2015 Society of Chemical Industry.

Optimization of the dilute maleic acid pretreatment of wheat straw.

BACKGROUND: In this study, the dilute maleic acid pretreatment of wheat straw is optimized, using pretreatment time, temperature and maleic acid concentration as design variables. A central composite design was applied to the experimental set up. The response factors used in this study are: (1) glucose benefits from improved enzymatic digestibility of wheat straw solids; (2) xylose benefits from the solubilization of xylan to the liquid phase during the pretreatment; (3) maleic acid replenishment costs; (4) neutralization costs of pretreated material; (5) costs due to furfural production; and (6) heating costs of the input materials. For each response factor, experimental data were fitted mathematically. After data translation to euro/Mg dry straw, determining the relative contribution of each response factor, an economic optimization was calculated within the limits of the design variables. RESULTS: When costs are disregarded, an almost complete glucan conversion to glucose can be reached (90% from solids, 7%-10% in liquid), after enzymatic hydrolysis. During the pretreatment, up to 90% of all xylan is converted to monomeric xylose. Taking cost factors into account, the optimal process conditions are: 50 min at 170 degrees C, with 46 mM maleic acid, resulting in a yield of 65 euro/Mg (megagram = metric ton) dry straw, consisting of 68 euro/Mg glucose benefits (from solids: 85% of all glucan), 17 euro/Mg xylose benefits (from liquid: 80% of all xylan), 17 euro/Mg maleic acid costs, 2.0 euro/Mg heating costs and 0.68 euro/Mg NaOH costs. In all but the most severe of the studied conditions, furfural formation was so limited that associated costs are considered negligible. CONCLUSIONS: After the dilute maleic acid pretreatment and subsequent enzymatic hydrolysis, almost complete conversion of wheat straw glucan and xylan is possible. Taking maleic acid replenishment, heating, neutralization and furfural formation into account, the optimum in the dilute maleic acid pretreatment of wheat straw in this study is 65 euro/Mg dry feedstock. This is reached when process conditions are: 50 min at 170 degrees C, with a maleic acid concentration of 46 mM. Maleic acid replenishment is the most important of the studied cost factors.