| 1. |
- Ahlgren, Serina, et al.
(författare)
-
Nitrogen fertiliser production based on biogas - Energy input, environmental impact and land use
- 2010
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 101, s. 7181-7184
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present paper was to investigate the land use, environmental impact and fossil energy use when using biogas instead of natural gas in the production of nitrogen fertilisers The biogas was assumed to be produced from anaerobic digestion of ley grass and maize. The calculations showed that 1 ha of agricultural land in south-west Sweden can produce 1.7 metric ton of nitrogen in the form of ammonium nitrate per year from ley grass, or 3 6 ton from maize The impact on global warming, from cradle to gate, was calculated to be lower when producing nitrogen fertiliser from biomass compared with natural gas Eutrophication and acidification potential was higher in the biomass scenarios The greatest advantage of the biomass systems however lies in the potential to reduce agriculture's dependency on fossil fuels In the biomass scenarios, only 2-4 MJ of primary fossil energy was required, while 35 MJ/kg N was required when utilising natural gas (C) 2010 Elsevier Ltd All rights reserved
|
|
| 2. |
- Alriksson, Björn, et al.
(författare)
-
Improving the fermentability of enzymatic hydrolysates of lignocellulose through chemical in-situ detoxification with reducing agents
- 2011
-
Ingår i: Bioresource Technology. - : Elsevier Ltd. - 0960-8524 .- 1873-2976. ; 102:2, s. 1254-1263
-
Tidskriftsartikel (refereegranskat)abstract
- Inhibitory lignocellulose hydrolysates were treated with the reducing agents dithionite and sulfite to achieve improved fermentability. Addition of these reducing agents (in the concentration range 5.0-17.5mM) to enzymatic hydrolysates of spruce wood or sugarcane bagasse improved processes based on both SHF (simultaneous hydrolysis and fermentation) and SSF (simultaneous saccharification and fermentation). The approach was exemplified in ethanolic fermentations with Saccharomyces cerevisiae and by using hydrolysates with sugar concentrations >100g/L (for SHF) and with 10% dry-matter content (for SSF). In the SHF experiments, treatments with dithionite raised the ethanol productivities of the spruce hydrolysate from 0.2 to 2.5g×L(-1)×h(-1) and of the bagasse hydrolysate from 0.9 to 3.9g×L(-1)×h(-1), values even higher than those of fermentations with reference sugar solutions without inhibitors. Benefits of the approach include that the addition of the reducing agent can be made in-situ directly in the fermentation vessel, that the treatment can be performed at a temperature and pH suitable for fermentation, and that the treatment results in dramatically improved fermentability without degradation of fermentable sugars. The many benefits and the simplicity of the approach offer a new way to achieve more efficient manufacture of fermentation products from lignocellulose hydrolysates.
|
|
| 3. |
- Azeem, Muhammad, et al.
(författare)
-
Sustainable bio-production of styrene from forest waste
- 2013
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 144, s. 684-688
-
Tidskriftsartikel (refereegranskat)abstract
- A strain of Penicillium expansum was studied for the production of styrene using forest waste biomass as a feeding substrate. The fungal strain was cultivated on bark of various trees supplemented with yeast extract and the volatiles produced were collected on Tenax TA and analyzed by gas chromatography-mass spectrometry. Fungus cultured on grated soft bark of pine (Pinus sylvestris) stems (GPB) and mature bark of oak (Quercus robur) supplemented with yeast extract produced relatively the highest amounts of styrene. The maximum styrene production rate was 52.5 mu g/h, 41 mu g/h and 27 mu g/h from fungus cultivated on 50 mL liquid media with 10 g GPB or mature bark of oak and potato dextrose broth respectively. These promising results suggest that the fungal strain could be used to produce "green" styrene plastics using renewable forest waste biomass.
|
|
| 4. |
- Badshah, Malik, et al.
(författare)
-
Anaerobic treatment of methanol condensate from pulp mill compared with anaerobic treatment of methanol using mesophilic UASB reactors.
- 2012
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 125C, s. 318-327
-
Tidskriftsartikel (refereegranskat)abstract
- The feasibility of anaerobic treatment of methanol condensate from pulp and paper mill in UASB reactor was investigated and compared with the anaerobic treatment of methanol. The UASB reactor treating methanol condensate was operated for 480days with minimum problems of overload. COD removal from methanol condensate and methanol under normal operating conditions ranged from 84-86% to 86-98%, respectively. Under optimal conditions (OLR=5.0gCODL(-1)day(-1), COD(influent)=11.40gL(-1)) a methane yield of 0.29 NL CH(4) per g COD(removed) (at standard temperature and pressure) was achieved during the treatment of methanol condensate. The recovery time of the microorganisms after several overloads was decreasing each time probably due to the adaptation to methanol condensate. These findings indicate that methanol condensate can be efficiently treated in a UASB reactor with the benefit of biogas production. As a bonus effect of the treatment, much of the smell of the feed was eliminated.
|
|
| 5. |
- Badshah, Malik, et al.
(författare)
-
Use of an Automatic Methane Potential Test System for evaluating the biomethane potential of sugarcane bagasse after different treatments.
- 2012
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 114, s. 262-269
-
Tidskriftsartikel (refereegranskat)abstract
- A multi-channel analyzer was used to evaluate biogas potential of sugarcane bagasse (SCB). The Automatic Methane Potential Test System contained fifteen parallel reactors and the same number of gas flow meters attached to the acquisition system. The set of reactors - gas flow meters gave reproducible results during anaerobic digestion of chemically defined carbon source and the units were used to evaluate the biomethane potential of SCB after different pretreatments, such as treatment with water, acid, acid followed by enzymatic treatment and acid followed by treatment with inactive enzymes. Combined pretreatment with 2% sulphuric acid and enzymatic hydrolysis (3.5% enzymes) resulted in conversion of 79% to monomeric sugars present in SCB. SCB treated with acid followed by enzymatic hydrolysis achieved the methane yield of 200NL per kg VS(added). Enzymatic saccharification of acid pretreated SCB resulted in increase of methane yield by 16±5% compared to that from acid treated SCB.
|
|
| 6. |
- Cadena, Edith M., et al.
(författare)
-
On hexenuronic acid (HexA) removal and mediator coupling to pulp fiber in the laccase/mediator treatment
- 2011
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 102:4, s. 3911-3917
-
Tidskriftsartikel (refereegranskat)abstract
- Flax soda/AQ pulps were treated with different fungal laccase-mediator combinations followed by physical and chemical characterization of the pulps to obtain a thorough understanding of the laccase/mediator effects on hexenuronic acid (HexA) removal and the coupling of mediator onto pulps for fiber functionalization. Large differences were found and the presence of lauryl gallate (LG) during Trametes villosa laccase (TvL) treatment (TvL + LG) resulted in a much larger reduction of pulp-linked HexA than the combination of p-coumaric acid (PCA) and Pycnoporus cinnabarinus laccase (PcL). A major portion of LG became attached to the pulp as revealed by an increase in the kappa number and further confirmed by thioacidolysis and H-1 NMR analysis of solubilized pulp fractions. Additional experiments with other chemical pulps and isolated pulp xylan and lignin revealed that HexA seems to be the sole pulp component attacked by TvL + LG. As a substrate for TvL, the reaction preference order is PCA > HexA > LG.
|
|
| 7. |
- Cavka, Adnan, et al.
(författare)
-
Detoxification of lignocellulosic hydrolysates using sodium borohydride
- 2013
-
Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 136, s. 368-376
-
Tidskriftsartikel (refereegranskat)abstract
- Addition of sodium borohydride to a lignocellulose hydrolysate of Norway spruce affected the fermentability when cellulosic ethanol was produced using Saccharomyces cerevisiae. Treatment of the hydrolysate with borohydride improved the ethanol yield on consumed sugar from 0.09 to 0.31 g/g, the balanced ethanol yield from 0.02 to 0.30 g/g, and the ethanol productivity from 0.05 to 0.57 g/(L×h). Treatment of a sugarcane bagasse hydrolysate gave similar results, and the experiments indicate that sodium borohydride is suitable for chemical in-situ detoxification. The model inhibitors coniferyl aldehyde, p-benzoquinone, 2,6-dimethoxybenzoquinone, and furfural were efficiently reduced by treatment with sodium borohydride, even under mild reaction conditions (20°C and pH 6.0). While addition of sodium dithionite to pretreatment liquid from spruce improved enzymatic hydrolysis of cellulose, addition of sodium borohydride did not. This result indicates that the strong hydrophilicity resulting from sulfonation of inhibitors by dithionite treatment was particularly important for alleviating enzyme inhibition.
|
|
| 8. |
- Chen, Xiaowen, et al.
(författare)
-
Kinetics and mechanism of autohydrolysis of hardwoods
- 2010
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 101:20, s. 7812-7819
-
Tidskriftsartikel (refereegranskat)abstract
- Autohydrolysis using water is a promising method to extract hemicelluloses from wood prior to pulping in order to make co-products such as ethanol and acetic acid besides pulp. Many studies have been carried out on the kinetics and mechanism of autohydrolysis using batch reactors. The present study was performed in a continuous mixed flow reactor where the wood chips are retained in a basket inside the reactor. This reactor is well suited to determine intrinsic kinetics of hemicellulose dissolution because the dissolved products are rapidly removed from the reactor, thus minimizing further hydrolysis and degradation of the hemicelluloses in solution. The xylan removal rate follows an S-shaped behavior. GPC analysis of the continuously removed extract shows that the dissolved xylan oligomers have a DP smaller than about 25. Lignin-free xylan oligomers and cellulose oligomers are the major components dissolved in the initial stage of autohydrolysis, while xylan covalently bound to lignin (i.e. an LCC) is the major component removed during the later stage of autohydrolysis. The molecular weight of the dissolved components decreases with time in the second stage. The kinetics of xylan removal are explained in terms of a mechanism based on recent knowledge of the ultrastructure of the cell fibre wall.
|
|
| 9. |
- Crespo, Carla, et al.
(författare)
-
Ethanol production by continuous fermentation of d-(+)-cellobiose, d-(+)-xylose and sugarcane bagasse hydrolysate using the thermoanaerobe Caloramator boliviensis.
- 2012
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 103:1, s. 186-191
-
Tidskriftsartikel (refereegranskat)abstract
- The recently isolated anaerobic bacterium Caloramator boliviensis with an optimum growth temperature of 60°C can efficiently convert hexoses and pentoses into ethanol. When fermentations of pure sugars and a pentose-rich sugarcane bagasse hydrolysate were carried out in a packed bed reactor with immobilized cells of C. boliviensis, more than 98% of substrates were converted. Ethanol yields of 0.40-0.46g/g of sugar were obtained when sugarcane bagasse hydrolysate was fermented. These features reveal interesting properties of C. boliviensis in producing ethanol from a renewable feedstock.
|
|
| 10. |
- Damayanti, A., et al.
(författare)
-
Respirometric analysis of activated sludge models from palm oil mill effluent
- 2010
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 1873-2976 .- 0960-8524. ; 101:1, s. 144-149
-
Tidskriftsartikel (refereegranskat)abstract
- Activated sludge models (ASMs) have been widely used as a basis for further model development in wastewater treatment processes. Values for parameters to be used are vital for the accuracy of the modeling approach. A continuous stirred tank reactor (CSTR), as open respirometer with continuous flow for 20 h is used in ASMs. The dissolved oxygen (DO) profile for 11 days was monitored. It was found the mass transfer coefficient K-La is 0.3 h(-1) during lag and start feed phase and 0.01 h(-1) during stop feed phase, while the heterotrophic yield coefficient Y-H is 0.44. Some of the chemical oxygen demand (COD) fractionations of palm oil mill effluent (POME) using respirometric test in ASM models are S-s 50 mg/L, S-1 16,600 mg/L, X-S 25,550 mg/L, and X-1 2,800 mg/L The comparison of experimental and ASM I from OUR concentration is found to fit well. (C) 2009 Elsevier Ltd. All rights reserved.
|
|
