• Energy Research

Abstract The oil scarcity and the rise in earth temperature have elevated the interest in lignocellulosic biorefineries. Lignin has high potential to be used in various applications including the production of biomaterials and transportation fuels. Among the different sources of lignin, organosolv lignin has the advantage of being sulphur-free and of low ash content compared to other types of industrial lignin. The present study focuses on cradle-to-gate life cycle and cost assessment of a novel organosolv lignin production process from spruce bark. The system boundary included production of tannin, lignin from spruce bark and handling of waste including all the inputs (material and energy) and outputs (emissions) in the process. Baseline scenario and scenarios S1 and S2 were compared to identify the most environmentally and economically suitable scenario. The baseline scenario is lignin production with co-production of tannin and tannin free bark (TFB) from spruce bark; scenario S1 is lignin production from TFB; and scenario S2 is lignin production from TFB with mass allocation. The functional unit was 1 kg lignin produced and ReCiPe 2016 Midpoint (H) method was used for the environmental impact assessment. The results showed that the baseline scenario had higher global warming potential (GWP) (2.14 kg CO2eq.) and total cost (1.959 €/kg) than S1 (1.39 kg CO2 eq. and 1.377 €/kg respectively) and S2 (0.23 kg CO2eq. and 0.998 €/kg respectively) scenarios. The results of sensitivity analysis showed that the use of bioethanol instead of ethanol reduced the burden on GWP but increased the burden on the land use impact category.

Abstract The oil scarcity and the rise in earth temperature have elevated the interest in lignocellulosic biorefineries. Lignin has high potential to be used in various applications including the production of biomaterials and transportation fuels. Among the different sources of lignin, organosolv lignin has the advantage of being sulphur-free and of low ash content compared to other types of industrial lignin. The present study focuses on cradle-to-gate life cycle and cost assessment of a novel organosolv lignin production process from spruce bark. The system boundary included production of tannin, lignin from spruce bark and handling of waste including all the inputs (material and energy) and outputs (emissions) in the process. Baseline scenario and scenarios S1 and S2 were compared to identify the most environmentally and economically suitable scenario. The baseline scenario is lignin production with co-production of tannin and tannin free bark (TFB) from spruce bark; scenario S1 is lignin production from TFB; and scenario S2 is lignin production from TFB with mass allocation. The functional unit was 1 kg lignin produced and ReCiPe 2016 Midpoint (H) method was used for the environmental impact assessment. The results showed that the baseline scenario had higher global warming potential (GWP) (2.14 kg CO2eq.) and total cost (1.959 €/kg) than S1 (1.39 kg CO2 eq. and 1.377 €/kg respectively) and S2 (0.23 kg CO2eq. and 0.998 €/kg respectively) scenarios. The results of sensitivity analysis showed that the use of bioethanol instead of ethanol reduced the burden on GWP but increased the burden on the land use impact category.

Alternative routes for carbon capture and storage are needed. This article evaluates the carbonic anhydrase effect on improving CO2 capture with alkaline residues for application in mineral storage.

Alternative routes for carbon capture and storage are needed. This article evaluates the carbonic anhydrase effect on improving CO2 capture with alkaline residues for application in mineral storage.

Utilization of biomass and reuse of industrial by-products and their sustainable and resource-efficient development into products that are inherently non-toxic is important to reduce the use of hazardous substances in the design, manufacture and application of biomaterials. The hypothesis in this study is that spent mushroom substrate (SMS), a by-product from mushroom production, has already undergone a biological pretreatment and thus, can be used directly as a starting material for fibrillation into value-added and functional biomaterial, without the use of toxic substances. The study show that SMS can be effectively fibrillated at a very high concentration of 6.5 wt % into fibrils using an energy demand of only 1.7 kWh kg-1, compared to commercial and chemically pretreated wood pulp at 8 kWh kg-1, under same processing conditions. SMS is a promising resource for fibrillation with natural antioxidant activity and network formation ability, which are of interest to explore further in applications such as packaging. The study shows that biological pretreatment can offer lower environmental impact related to toxic substances emitted to the environment and thus contribute to reduced impacts on categories such as water organisms, human health, terrestrial organisms, and terrestrial plants compared to chemical pretreatments.

Utilization of biomass and reuse of industrial by-products and their sustainable and resource-efficient development into products that are inherently non-toxic is important to reduce the use of hazardous substances in the design, manufacture and application of biomaterials. The hypothesis in this study is that spent mushroom substrate (SMS), a by-product from mushroom production, has already undergone a biological pretreatment and thus, can be used directly as a starting material for fibrillation into value-added and functional biomaterial, without the use of toxic substances. The study show that SMS can be effectively fibrillated at a very high concentration of 6.5 wt % into fibrils using an energy demand of only 1.7 kWh kg-1, compared to commercial and chemically pretreated wood pulp at 8 kWh kg-1, under same processing conditions. SMS is a promising resource for fibrillation with natural antioxidant activity and network formation ability, which are of interest to explore further in applications such as packaging. The study shows that biological pretreatment can offer lower environmental impact related to toxic substances emitted to the environment and thus contribute to reduced impacts on categories such as water organisms, human health, terrestrial organisms, and terrestrial plants compared to chemical pretreatments.

Enzymatic hydrolysis is a key step in bioethanol production. Efficient hydrolysis requires a consortium of different enzymes that are able to hydrolyze cellulose and hemicellulose into fermentable sugars. Myceliopthora thermophila is a promising candidate for the production of thermophilic cellulolytic enzymes, the use of which could reduce the cost of ethanol production. The growth conditions of the fungus were optimized in order to achieve increased secretion of extracellular cellulases. Optimal conditions were found to be 7.0% w/v brewer’s spent grain as the carbon source and 0.4% w/v ammonium sulfate as the nitrogen source. The cellulases obtained were characterized for their optimum activity. The optimum temperature and pH for cellulase activity are 65 °C and pH 5.5, respectively. Studies on thermal inactivation of the crude extract showed that the cellulases of M. thermophila are stable for temperatures up to 60 °C. At this temperature the half-life was found to be as high as 27 h. Enzymatic hydrolysis of cellulose resulted in 31.4% hydrolysis yield at 60 °C after 24 h of incubation. Finally, the recalcitrance constant for cellulose and cellulose pretreated with ionic liquids was calculated to be 5.46 and 2.69, respectively.