首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The present study on flash hydrolysis under subcritical water medium capitalizes on the difference in reaction kinetics of algae polymeric components and fractionates proteins in liquid phase in seconds of residence time. All the experiments were conducted using flocculated Scenedesmus sp. cultivated in the laboratory using photobioreactors. The effect of temperature and residence time on protein hydrolysis to water-soluble fractions (algal hydrolyzate) and yield of lipid-rich solids (biofuels intermediate) was studied using a lab-scale continuous flow reactor.More than 60 wt% of the total nitrogen content (dry basis) in Scenedesmus sp. was extracted within 10 s of residence time above 240 °C. The ion chromatography and NMR spectra of the algal hydrolyzate showed that the extracted proteins were present both as free amino acids and peptides. The carbon content of biofuels intermediate increased up to 66 wt% making it lipid- and energy-dense feedstock suitable for biofuels production. The scanning electron microscope image of biofuels intermediate indicated that the solids were globular and smaller in size as compared to the untreated microalgae.  相似文献   

2.
Gasification of microalgae feedstock generates mineral ash. In this work, raw ash is produced from lipid‐extracted algal biomass of the Nannochloropsis salina strain. Prior to using it as filler for composite fabrication with poly(vinyl alcohol), raw ash (RASH) is activated with NaOH and surface modified with (3‐aminopropyl)triethoxysilane. Surface modification of activated ash (PASH) significantly improves interfacial interaction between surface‐modified ash (GASH) and polymer matrix. Higher ultimate tensile strength of PVA/GASH composites is recorded, compared with PVA/RASH and PVA/PASH. Young's modulus of biocomposites appears to increase proportionally to loading of the fillers. Thermal properties of polymeric materials of PVA with these ashes are stable. This is the first report to demonstrate the utilization of microalgal ash, the leftover after completed gasification of algal biomass, as an efficient filler for production of value‐added polymeric materials. It is proposed that microalgal ash is capable of improving the economic feasibility of microalgae‐based biorefinery. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43599.  相似文献   

3.
BACKGROUND: Hydroponic greenhouse effluent has high concentrations of total phosphorus (30–100 mg PO4‐P L?1) and nitrates (200–300 mg NO3‐N L?1). Current technologies for effluent treatment have limitations of performance and high maintenance costs. The goals of this study were to investigate strategies which combine alkali treatment and microalgae cultivation for removal of nutrients from hydroponic greenhouse effluent. RESULTS: Treatment with strong alkali was found to effectively remove 97% of total phophorous especially in the form of phosphate, without affecting the nitrate ion concentration in the greenhouse effluent. After alkali treatment, marine algae Dunaliella salina (UTEX 1644) cultivation on treated hydroponic effluent (pH 7.5) showed > 80% decrease in nitrate content in the effluent within 4 days of cultivation. In the same period, the carotene content of the micro‐algal system was in the range 0.5 ± 0.02 µg mg?1 (dry cell weight) which was 1.5 times higher than in the control. CONCLUSION: This study demonstrated that combination of a conventional alkali precipitation method with a microalgae treatment system is a highly efficient approach for the removal of excess nutrients from hydroponic greenhouse effluent in a short treatment time. The microalgae can provide a source of value in the form of carotene. © 2012 Society of Chemical Industry  相似文献   

4.
Cultivation of microalgae has potential in producing a feedstock for biofuels and, in addition, high‐value lipid bioproducts such as long‐chain (⪈C20, LC) omega‐3 oils, carotenoid pigments and squalene, as well as other non‐lipid materials including exopolysaccharide. The high‐value LC omega‐3 oils have been conventionally sourced from fish. This paper provides a perspective on our recent study of the heterotrophic growth of thraustochytrids for their wider biotechnological potential, including as a source of a range of higher value lipids in addition to biofuels.  相似文献   

5.
在高温液态水处理的甘蔗渣酶解过程中添加Tween80可使聚糖转化率提高11.4%。根据蔗渣酶解液中糖的种类及含量,用葡萄糖、木糖和纤维二糖标准品模拟蔗渣酶解液组成配制成相应的混合糖培养基,同时配制仅含葡萄糖的培养基,在有、无Tween80和BG11(Blue-Green 11)的条件下,考察小球藻在不同培养基中的异养生长及脂肪酸生成。结果显示Tween80对小球藻的生长具有抑制作用,纤维二糖也会影响小球藻的生长;小球藻在添加BG11的葡萄糖培养基中的生物量最高,为1.97 g·L-1,在添加BG11的蔗渣酶解液中的生物量高出未添加BG11的2倍,在含有Tween80和BG11的蔗渣酶解液中的总脂肪酸含量最高,达到6.90%,在所有培养基中产生的脂肪酸以C16:0、C18:1、C18:3、C20:1和C20:4为主;培养基组成优化可进一步提高微藻生物量和油脂产量。  相似文献   

6.
Lignocellulosic biomass is an abundant, renewable source of polysaccharides that could be available in amounts sufficient to provide a source of sugars for carbon neutral biofuel production. We review the background to biofuels production in the US from corn sugars and subsequent R and D efforts to saccharify plant biomass to provide an alternative sugar source. Research efforts and programs have generally not addressed the key technical hurdles in providing a commodity‐scale supply of biomass and in developing biological routes to saccharify it at high yields. Techno‐economic analyses of proposed processes highlight the importance of biomass cost, the role of pretreatment on both inhibitor generation, and the contribution of enzyme costs to saccharification. Alternatives, such as the production of fatty acids by microalgae, have comparable technical hurdles. Although there is a regulatory framework for biofuels, which is discussed, a credible biological process for large‐scale, cost‐effective production of lignocellulosic biofuels remains elusive. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2689–2701, 2015  相似文献   

7.
Regiospecific distributions of fatty acids of triacylglycerols (TAG) and phospholipids (PL) separated from broad beans (Vicia faba) of four cultivars (Minpo, Sanuki, Nintoku and Sanren) were investigated. The major lipid components were PL (47.5–50.5 wt‐%) and TAG (47.7–50.1 wt‐%), while steryl esters, hydrocarbons, free fatty acids, diacylglycerols and monoacylglycerols were present in minor proportions (1.6–2.4 wt‐%). The PL components isolated from the four cultivars were phosphatidylcholine (56.4–58.4 wt‐%), phosphatidylethanolamine (20.3–21.7 wt‐%) and phosphatidylinositol (16.6–18.6 wt‐%). Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among these PL. The principal characteristics of the fatty acid distribution in the TAG and PL were evident in the beans: Unsaturated fatty acids were predominantly concentrated in the sn‐2 position while saturated fatty acids primarily occupied the sn‐1 or sn‐3 position in these lipids. The lipid components and fatty acid distributions were almost the same in the four cultivars and were not influenced by genetic variability and planting location. These results could be useful information to both consumers and producers for the manufacture of traditional broad bean foods in Japan.  相似文献   

8.
Flexible silk fibroin gel‐like films with microporous morphology were prepared from B. mori silk fibroin fibers directly solubilized in formic acid/CaCl2 solvent. These films were characterized by several analysis techniques to determine the structure and properties of films. The pore size of gel‐like films can be adjusted through SF concentration and Ca ions concentration. The controllable pore size in gel‐like films was grew from 3–5 μm to 100 μm under the increase of fibroin concentration from 1.0 wt % to 8.0 wt %. At the same time, the water content of silk fibroin gel‐like film decreased from 83.5 ± 3.4% to 68.2 ± 2.6%. With increasing Ca ions contents from 2.0 wt % to 10.0 wt % in dissolution process, the pore size and water content of silk fibroin gel‐like films grew larger, especially its water content values reached 86.2 ± 4.0% at 10.0 wt % Ca ions concentration. At wet condition, the gel‐like film with β‐sheet structure showed higher breaking stress (4.26 ± 0.31 MPa) and elongation (45.45 ± 15.79%) at 8.0 wt % concentration. With the preparation method, the membrane is hydrophilic and the pore size is adjustable, which contributes to high toughness and favorable cell growth environment, suggesting that these silk fibroin gel‐like films can be a potential candidate scaffold for biomedical applications, such as wound dressing, facial mask, contact lenses, etc. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41842.  相似文献   

9.
Fly ash, inexpensive and not eco‐friendly material, is the residue from the coal burning in thermal power stations. If ways can be found to use it, it will facilitate applications for the ash materials and simultaneously reduce the pollution. In this study, silane‐grafted ultrafine fly ash (S‐UFA) was used as a reinforcing filler in poly(lactic acid) (PLA) to prepare a series of PLA/S‐UFA composites. The tensile strength of PLA/S‐UFA composites increases with the increase of S‐UFA content when less than 20 wt %; after a loading fraction greater than 30 wt %, the tensile strength of the composites decreases with the increasing S‐UFA weight fraction. The morphology of PLA/S‐UFA composites was observed by scanning electron microscope (SEM). X‐ray diffraction (XRD) analysis was applied to investigate the crystal structure of S‐UFA and the composites. The thermal properties of these composites were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA results showed that the thermal stability of PLA/S‐UFA composites slightly decreased with the increasing S‐UFA loading fraction. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43716.  相似文献   

10.
The fatty acid distributions of triacylglycerols (TAG) and major phospholipids (PL) obtained from adzuki beans (Vigna angularis) were investigated. The total lipids extracted from the beans were separated by thin‐layer chromatography (TLC) into eight fractions. The major lipid components were PL (63.5 wt‐%), TAG (21.2 wt‐%), steryl esters (7.5 wt‐%) and hydrocarbons (5.1 wt‐%), while free fatty acids, diacylglycerols (1,3‐DAG and 1,2‐DAG) and monoacylglycerols were also present in minor proportions (0.2–1.1 wt‐%). The major PL components isolated from the beans were phosphatidylcholine (45.3 wt‐%), phosphatidylethanolamine (25.8 wt‐%) and phosphatidylinositol (21.5 wt‐%). Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among the three PL. With a few exceptions, however, the principal characteristics of the fatty acid distribution in the TAG and three PL were evident in the beans: Unsaturated fatty acids were predominantly concentrated in the sn‐2 position while saturated fatty acids primary occupied the sn‐1 or sn‐3 position in the oils of the adzuki beans. In general, these results could be useful to both consumers and producers for the manufacture of traditional adzuki foods in Japan.  相似文献   

11.
Schizochytrium sp. is considered as a promising alternative commercial source of docosahexaenoic acid (DHA), but the production is hindered by the high feedstock cost. In this study, inulin is used as a cheap and readily available feedstock for Schizochytrium sp. ATCC 20888 to produce DHA. The strain could not utilize inulin directly and therefore inulin first needed to be hydrolyzed. Compared with the acidic hydrolyzate by HCl and hydrolyzate by endo‐inulinase, the hydrolyzate by exo‐inulinase serves as the most effective carbon source for microalgal growth. Hydrolysis of inulin by exo‐inulinase is further optimized, and up to 97.8% of inulin conversion is obtained under the optimal conditions of 40 °C, pH 7.0, substrate concentration of 80 g L?1 and exo‐inulinase loading of 2 g kg?1 substrate for 12 h. The resulting hydrolyzate containing mainly fructose is used for the DHA production by the microalga. The lipid content in biomass, DHA content in total fatty acids, DHA yield, and DHA productivity at 72 h reach 45.26%, 35.59%, 5.64 g L?1 and 1.88 g L?1 d?1, respectively. The results suggest that inulin is an excellent feedstock for Schizochytrium sp. suitable for commercial DHA production. Practical Applications: DHA is an essential nutrient for human health and is widely used in infant formula and functional food. As a reserve carbohydrate, inulin present in plants represents a cheap, abundant, and readily available bioresource. This study describes the suitability of inulin as a promising alternative to glucose for DHA production by Schizochytrium sp. Hence, a practical bioprocess for commercial DHA production from inulin by Schizochytrium sp. could be developed. As far as it is known, this is the first report of inulin as a feedstock for Schizochytrium sp. to produce DHA.  相似文献   

12.
BACKGROUND: As a potential source of biomass, Jerusalem artichoke has been studied for bioethanol production; however, thus far it has not been investigated for the production of other liquid biofuels, such as biodiesel. This work aims to develop a novel approach for biodiesel production from Jerusalem artichoke tuber using heterotrophic microalgae. RESULTS: In this study, Chlorella protothecoides utilized hydrolysate of Jerusalem artichoke tuber as carbon source and accumulated lipid in vivo, with lipid content as high as 44% by dry mass, and a carbon source to lipid conversion ratio of about 25% in a 4‐day scale cultivation. The lipids were extracted and then converted into biodiesel by transesterification. Cetane acid methyl ester, linoleic acid methyl ester and oleic acid methyl ester were the dominating components of the biodiesel produced. Unsaturated fatty acids methyl ester constituted over 82% of the total biodiesel content. CONCLUSION: This work suggests the feasibility of an alternative method of producing biodiesel from Jerusalem artichoke tuber using microalgae cultivation, and a cost reduction of carbon source feed in algal oil production can be expected. Copyright © 2009 Society of Chemical Industry  相似文献   

13.
Recycled high‐density polyethylene (RHDPE)/coir fiber (CF)‐reinforced biocomposites were fabricated using melt blending technique in a twin‐screw extruder and the test specimens were prepared in an automatic injection molding machine. Variation in mechanical properties, crystallization behavior, water absorption, and thermal stability with the addition of fly ash cenospheres (FACS) in RHDPE/CF composites were investigated. It was observed that the tensile modulus, flexural strength, flexural modulus, and hardness properties of RHDPE increase with an increase in fiber loading from 10 to 30 wt %. Composites prepared using 30 wt % CF and 1 wt % MA‐g‐HDPE exhibited optimum mechanical performance with an increase in tensile modulus to 217%, flexural strength to 30%, flexural modulus to 97%, and hardness to 27% when compared with the RHDPE matrix. Addition of FACS results in a significant increase in the flexural modulus and hardness of the RHDPE/CF composites. Dynamic mechanical analysis tests of the RHDPE/CF/FACS biocomposites in presence of MA‐g‐HDPE revealed an increase in storage (E′) and loss (E″) modulus with reduction in damping factor (tan δ), confirming a strong influence between the fiber/FACS and MA‐g‐HDPE in the RHDPE matrix. Differential scanning calorimetry, thermogravimetric analysis thermograms also showed improved thermal properties in the composites when compared with RHDPE matrix. The main motivation of this study was to prepare a value added and low‐cost composite material with optimum properties from consumer and industrial wastes as matrix and filler. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42237.  相似文献   

14.
We investigated nonisothermal (fast) and nominally isothermal hydrothermal liquefaction (HTL) of Nannochloropsis sp. microalgae for the production of biocrude. Biocrude yields ranged from 36 to 45 wt % (dry weight), with fast HTL with low mass loading giving the highest yield. This condition also gave the biocrude with the lowest heating value, which indicates there are compromises to be made between biocrude quantity and quality. The aqueous phase and biocrude product fractions were characterized using elemental analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS). This detailed level of analysis identified more than 30,000 unique molecular products. The aqueous phase products included compounds with the same molecular formulae as known herbicides, which may inform efforts in genetic engineering of algae and/or bacteria for cultivation on the aqueous phase. This detailed molecular‐level characterization provides some clues regarding the types of reactions that may take place during HTL. © 2016 American Institute of Chemical Engineers AIChE J, 62: 815–828, 2016  相似文献   

15.
A pilot polygeneration process of a 75 t h–1 circulating fluidized bed (CFB) boiler combined with a moving bed coal pyrolyzer was developed based on laboratory‐scale experimental results. The process operation showed good consistency and integration between boiler and pyrolyzer. Some critical operating parameters such as hot ash split flow from the CFB boiler to the pyrolyzer, mixing of hot ash and coal particles, control of pyrolysis temperature and solid inventory in the pyrolyzer, and pyrolysis gas clean‐up were investigated. Yields of 6.0 wt‐% tar and 8.0 wt‐% gas with a heating value of about 26 MJ m–3 at 600 °C were obtained. Particulate content in tar was restrained less than 4.0 wt‐% by using a granular filter of the moving bed. Operation results showed that this pilot polygeneration process was successfully scaled up.  相似文献   

16.
BACKGROUND: Microalgae continue to be a focus of industrial bioprocess sustainability practice owing to the numerous biofuels and bioproducts that can be obtained with simultaneous environmental bioremediation applications. However, the extremely dilute nature of large volume microalgal cultures and the small particle size of single‐cell microalgae present technological and economic problems of effective dewatering, thus affecting the application of microalgae in process industries. Microalgae immobilization using biocompatible polymeric systems has proved to be an effective strategy to circumvent the heavy dewatering requirement, as this approach provides physical separation between the solid microalgal cells and the liquid medium. RESULTS: In this work, a novel microalgae immobilization carrier, sodium cellulose sulphate/poly‐dimethyl‐diallyl‐ammonium chloride (NaCS‐PDMDAAC) capsule, was synthesized and the resulting polymeric capsules were characterized using physicochemical techniques such as Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy equipped with energy dispersive X‐ray spectroscopy (SEM‐EDX) and nuclear magnetic resonance spectroscopy (NMR). Experimental results showed that the unique properties of NaCS‐PDMDAAC capsules, such as pore size, capsule size, mechanical strength, and structural and compositional homogeneity, relevant to microalgae cultivation with batch or continuous nutrient removal can be accurately controlled. CONCLUSION: These polymeric capsules find applications not only with microalgae cultivation but also for other microorganisms. © 2012 Society of Chemical Industry  相似文献   

17.
Composites containing 50% wt fly ash (sourced from the UK and South Africa) in polypropylene homopolymer (manufacturer stabilized for general purpose use) have been prepared by using batch and continuous methods. The effect of the following coupling agents were investigated on the photo‐ and thermal‐decomposition of the composite materials: Lubrizol Solplus C800 (an unsaturated carboxylic acid), γ‐methacryloxypropyl trimethoxy silane (γ‐MPS), 1,3‐phenylene dimaleimide (BMI), and maleic anhydride‐grafted‐polypropylene (m‐PP). High melt, thermal‐, and photo‐stability was favored when the matrix was coupled to the filler surface by monomeric coupling agents that were expected to adsorb in a close packed layer on the fly ash surface. Further improvements were observed in cases where the coupling agent could also self‐polymerize. m‐PP did not lead to increased stability due to its low adsorption density on the fly ash surface. The relatively high water/acid soluble transition metal ion content of the UK sourced fly ash did not appear to affect stability under the test conditions employed in this study. The South African sourced fly ash had a higher level of quartz and mullite together with a high level of group 1 and 2 metals. The latter in particular may have led to debonding of the coupled interfacial region from the filler surface and possible adsorption of stabilizers on the pristine surface. This resulted in the South African fly ash generally possessing poorer resistance to oxidation than the UK fly ash. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39974.  相似文献   

18.
Stable waterborne poly(urethane‐urea) (WBPU; soft segment content: 57%; dimethylol propionic acid: 19 mol %/5.8 wt %)–polyacrylate(methyl methacrylate/n‐butyl acrylate) (weight ratio: 4/1) hybrid latex (emulsions) with different acrylic contents [0, 10, 20, 30, and 40 wt % based on poly(urethane‐urea)] and without external surfactant were successfully prepared by in situ polymerization during a prepolymer mixing process. However, the as‐polymerized hybrid latex containing 50 wt % of acrylic monomer content was found to be unstable, indicating that about 50 wt % of acrylic monomer content was beyond the limit value of self‐emulsifying ability of WBPU anionomer prepared in this study. The breadth of particle size distribution of hybrid latex increased markedly from 20–75 to 55–275 nm with increasing acrylic monomer content from 0 to 40 wt %. The pristine WBPU and hybrid latex samples containing 10, 20, and 30 wt % of acrylic monomer showed unimodal distributions, whereas the hybrid sample having 40 wt % acrylic monomer content displayed a bimodal distribution with the broadest breadth. As acrylic monomer content increased, the yield point of stress–strain curve, hardness, glass transition, and water resistance of hybrid film samples increased, whereas their abrasion resistance, elongation at break, and elasticity decreased. The tensile strength of hybrid film samples (10–30 wt % of acrylic monomer content) was almost the same as that of pristine WBPU film sample, indicating the intimate molecular mixing between poly(urethane‐urea) and polyacrylate molecules in hybrids. However, the hybrid sample having 40 wt % acrylic monomer showed significantly diminished performance, which might be due to the deviation from intimate molecular mixing. From these results, the optimum acrylic monomer content was found to be about 30 wt %, which realized reasonably advantages of both poly(urethane‐urea) and acrylic polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

19.
The application of microalgae biotechnology, which can recover nutrients from wastewater, improve water quality, and feed some aquatic animals, is becoming an emerging trend in the development of eco‐friendly aquaculture. Previous studies explored a variety of models to support the use of microalgae in aquaculture practice, verifying the feasibility and advantages of microalgae‐based aquaculture. However, a couple of bottlenecks and problems jeopardizing the application of microalgae biotechnology in aquaculture are discovered in the research and industrial practice. This work, hence, summarizes the research progress and the current opinions relating with the microalgae‐based aquaculture and proposes some critical thoughts about the bottlenecks challenging its industrial implementation. © 2020 Society of Chemical Industry (SCI)  相似文献   

20.
Seed oils from five legume cultivars of Phaseolus vulgaris, grown in Japan, were extracted and classified by thin‐layer chromatography (TLC) into seven fractions: hydrocarbons (HC; 0.7–1.4 wt‐%), steryl esters (SE; 1.7–3.3 wt‐%), triacylglycerols (TAG; 33.8–45.9 wt‐%), free fatty acids (FFA; 0.6–1.5 wt‐%), sn‐1,3‐diacylglycerols (1,3‐DAG; 0.3–1.0 wt‐%), sn‐1,2‐diacylglycerols (1,2‐DAG; 0.4–1.2 wt‐%) and phospholipids (PL; 49.4–58.8 wt‐%). Fatty acids derivatized as methyl esters were analyzed by gas chromatography (GC) and a flame ionization detector. Molecular species and the fatty acid distribution of TAG isolated from the total lipids in the beans were analyzed by a combination of argentation‐TLC and GC. A modified argentation‐TLC procedure, developed to optimize the separation of the complex mixture of total TAG, provided 18 different groups of TAG, based on both the degree of unsaturation and the total length of the three acyl chains of fatty acid groups. SDT (3.2–4.2 wt‐%), M2T (3.8–5.0 wt‐%), D3 (4.8–5.9 wt‐%), MDT (8.0–13.9 wt‐%), D2T (12.5–15.8 wt‐%), MT2 (19.4–22.7 wt‐%), DT2 (17.8–23.5 wt‐%) and T3 (9.2–13.0 wt‐%) were the main TAG components. The dominant fatty acids of TAG were α‐linolenic (48.5–57.8 wt‐%) and linoleic (16.7–25.8 wt‐%) acids, with appreciable amounts of palmitic (8.3–13.2 wt‐%) and oleic (7.8–13.8 wt‐%) acids. The high content of α‐linolenic acid in the cultivars of P. vulgaris could very likely play a beneficial role in reducing the risk of coronary heart disease among the large populations consuming them in Japan.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号