Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Appl Biochem Biotechnol ; 190(2): 423-436, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31376051

RESUMO

Lignocellulosic hydrolysate contains complex nonsugar compounds and undegraded sugars in the process of preparing platform compound levulinic acid (LA) and furfural by one-step dilute-acid hydrolysis. For efficiently and comprehensively utilizing the hydrolysate, a series of polar modified resins were synthesized for adsorption and separation of the sugarcane bagasse hydrolysate to obtain platform compounds and fermentable hydrolysate simultaneously. The adsorption capacities of LA and furfural were optimized to 85.32 mg/g and 33.55 mg/g on polar modified resin prepared with 80 wt% glycidyl methacrylate (GMA -80), which was much higher than nonpolar resin (4.16 mg/g and 16.14 mg/g). GMA-80 obtained the best comprehensive adsorption property, whose desorption rates were 99.90% and 89.86% for LA and furfural, respectively, and its regeneration performance was also excellent, indicating that the resin is a potential adsorbent and expected to be used in the separation and purification of the lignocellulosic hydrolysate.

2.
Bioresour Technol ; 299: 122625, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31881437

RESUMO

The production of high-purity xylobiose from lignocellulose is an expensive and tedious process. In this work, the production of xylobiose from enzymatic hydrolysis of alkaline oxidation pretreated sugarcane bagasse was investigated. Furthermore, a simple process for the separation of xylobiose from enzymatic hydrolysate by activated carbon absorption, water washing, and ethanol-water desorption was developed. Under the optimized separation conditions, 96.77% xylobiose was adsorbed at 16% activated carbon loadings. Moreover, xylose and acetate could not be detected after washing by 3-fold volume of water. Xylobiose with 80.16% yield was eluted by 5-fold volume of 5% (v/v) ethanol-water. The reusability of activated carbon was evaluated by 5 cycles of adsorption-desorption process, suggesting that the activated carbon exhibited good reusability. The separated xylobiose sample with high-purity (97.29%) was confirmed by HPLC, ESI-MS, and NMR. Overall, this study provided a low-cost and robust technology for the production and separation of high-purity xylobiose from lignocellulose.


Assuntos
Saccharum , Celulose , Dissacarídeos , Hidrólise
3.
Prep Biochem Biotechnol ; 49(6): 597-605, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30929602

RESUMO

A simple and accurate Nile Red fluorescent method was built to evaluate the lipid content of three different oleaginous yeasts by one standard curve. The staining of cells can be observed clearly by laser scanning confocal microscope, showing that Nile Red can enter into the cells of oleaginous yeasts easily. A series of conditions such as pretreating temperature, cell suspension concentration (OD600), staining time, Nile Red concentration and the type of suspension solvent were learnt systematically to obtain the optimal process parameters for Nile Red staining. After optimization, the fitting curve of Nile Red fluorescent method was established under suitable conditions (pretreating temperature: 50 °C, OD600: 1.0; staining time: 5 mins; Nile Red concentration: 1.0 µg/mL; suspension solvent: PBS) and it had a suitable correlation coefficient (R2 = 0.95) for lipid content measurement of different oleaginous yeasts. By this study, the possibility of lipid content determination of different oleaginous yeasts by one fitting curve can be proven and this will improve the efficiency of researches related to microbial lipid production.


Assuntos
Corantes Fluorescentes/química , Lipídeos/análise , Microscopia Confocal/métodos , Oxazinas/química , Leveduras/química , Cryptococcus/química , Lipomyces/química , Coloração e Rotulagem/métodos , Temperatura Ambiente , Trichosporon/química
4.
Bioresour Technol ; 283: 191-197, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30908983

RESUMO

Elephant grass (Pennisetum purpureum) acid hydrolysate was used as substrate for anaerobic digestion for the first time. Within short period (ten days), the organic materials (sugars and organic acids) in the elephant grass hydrolysate could be utilized efficiently for stable biogas production that the COD removal, biogas yield, and CH4 content were 91.3 ±â€¯2.0%, 0.561 ±â€¯0.014 m3/kg COD consumption, and 68.1 ±â€¯4.6%, respectively throughout this bioprocess. During anaerobic digestion, almost no volatile fatty acids (VFAs) was accumulated (merely <0.1 g/L acetic acid was found) and the outlet pH was very stable (7.3 ±â€¯0.1). Meanwhile, the furans including furfural and 5-hydroxymethylfurfural (HMF) existing in the inlet substrate could be degraded. After anaerobic digestion, the outlet effluent was treated by combination of Fe-C micro-electrolysis and Fenton reaction to remove 93.1% of residual COD and 98.6% of color. Considering the performance, cost, operation, and environmental influence, this technology is suitable for industrial treatment of waste elephant grass.


Assuntos
Biocombustíveis , Pennisetum/metabolismo , Anaerobiose , Reatores Biológicos , Ácidos Graxos Voláteis/metabolismo , Metano/metabolismo
5.
Sci Total Environ ; 663: 447-452, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30716636

RESUMO

Wastewater treatment is one important issue for turpentine plant and more wastewater generated by greater turpentine processing will prevent its further development. To solve this issue without extra place and new equipment, one industrial system for reuse and treatment of turpentine processing wastewater was introduced for the first time. For wastewater reuse, the technology was simple and easy to control that after neutralization by lime and absorption with activated carbon (optional, mostly not necessary), the wastewater could be reused for turpentine processing. After reuse, the wastewater was further treated by a biological system. During long-term application of wastewater reuse in this plant, it showed little influence on the products performance (mainly acid value) and final wastewater COD. Base on above advantages, the plant could decide when for wastewater drainage, and thus the amount of wastewater was reduced greatly. For the biological treatment, the COD of wastewater could be degraded to suitable level stably and the wastewater after treatment could be applied for daily life in the plant. Overall, considering the cost, operation, and performance, the whole system shows great potential and possibility of industrial application and therefore can be applied widely in the turpentine processing industry.

6.
Carbohydr Polym ; 208: 421-430, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30658820

RESUMO

Superabsorbent was synthesized from bacterial cellulose (BC) generated by in situ fermentation on bentonite inorganic gel (BIG). For BIG preparation, the effect of sodium agent's type and content, temperature and time of sodium-modification, and gelling agent's type and content on the viscosity of BIG were learned to optimize the synthesis process. For polymerization, the effect of different factors including ratio of monomer to substrate (modified BC from in situ fermentation), content of initiator and crosslinker, monomer neutralization degree, reaction temperature and time on the performance of composite (superabsorbent) synthesized were analyzed. Under optimal condition, the composite showed good water absorption, salts absorption, and water retention capacity. The original bentonite, sodium-based bentonite, BIG and composite structure was characterized by X-ray fluorescence (XRF), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA), and the characterization partly explained the performance of water absorption and thermal stability of the composite. Overall, this study provides one method for superabsorbent synthesis from low-cost and natural resources.


Assuntos
Bactérias/classificação , Celulose/metabolismo , Argila/química , Bentonita/química , Celulose/química , Fermentação , Água/química
7.
Bioresour Technol ; 275: 345-351, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30597396

RESUMO

High chemical input is required for enzymatic production of xylo-oligosaccharides (XOS) using xylan extracted from lignocellulosic biomass. In this study, enzymatic hydrolysis of alkaline oxidation (AO) treated sugarcane bagasse (SCB) directly for the production of XOS was conducted. The effect of AO pretreatment on the chemical compositions and hydrolytic properties of SCB was investigated. The AO pretreatment conditions with low chemical input for the production of XOS were optimized by orthogonal design. Stepwise enzymatic hydrolysis of AO pretreated SCB with xylanase and cellulase produced XOS (1.78 g/L), meanwhile, the cellulose conversion increased from 84.97% to 91.51% compared with directly enzymatic hydrolysis using cellulase. HPLC-UV and MALDI-TOF-MS analysis indicated that the obtained XOS products were mainly composed of xylobiose and xylose with a small amount of arabinose/4-O-methylglucuronic acid substituted xylotriose and xylotetraose. The proposed strategy for the co-production of functional XOS and fermentable sugars from SCB showed potential of industrial application.


Assuntos
Celulose/metabolismo , Oligossacarídeos/biossíntese , Saccharum/metabolismo , Açúcares/metabolismo , Álcalis , Biomassa , Fermentação , Hidrólise , Oxirredução
8.
Appl Biochem Biotechnol ; 188(3): 585-601, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30552624

RESUMO

An adsorption resin CX-6 was synthesized and used for acid soluble lignin (ASL) removal from sugarcane bagasse hydrolysate (SCBH). The adsorption conditions of pH value, amount of adsorbent, initial ASL concentration, and temperature on ASL adsorption were discussed. The results showed the adsorption capacity of ASL was negatively affected by increasing temperature, solution pH, and adsorbent dose, and was positively affected by increasing initial concentration. The maximum adsorption capacity of ASL was 135.3 mg/g at initial ASL concentration 6.46 g/L, adsorption temperature 298 K, and pH 1. Thermodynamic study demonstrated that the adsorption process was spontaneous and exothermic. Equilibrium and kinetics experiments were proved to fit the Freundlich isotherm model and pseudo-second-order model well, respectively. Fermentation experiment showed that the SCBH after combined overliming with resin adsorption as fermentation substrate for microbial lipid production by Trichosporon cutaneum and Trichosporon coremiiforme was as better as that of SCBH by combined overliming with active charcoal adsorption, and more efficient than that of SCBH only by overliming. Moreover, the regeneration experiment indicated that the CX-6 resin is easy to regenerate and its recirculated performance is stable. In conclusion, our results provide a promising adsorbent to detoxify lignocellulose hydrolysate for further fermentation.


Assuntos
Ácidos/química , Lignina/isolamento & purificação , Lipídeos/biossíntese , Saccharum/química , Adsorção , Fermentação , Concentração de Íons de Hidrogênio , Hidrólise , Lignina/química , Microscopia Eletrônica de Varredura , Solubilidade , Temperatura Ambiente , Termodinâmica , Trichosporon/metabolismo
9.
Materials (Basel) ; 11(10)2018 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-30250001

RESUMO

Gel polymer electrolyte (GPE) is widely considered as a promising safe lithium-ion battery material compared to conventional organic liquid electrolyte, which is linked to a greater risk of corrosive liquid leakage, spontaneous combustion, and explosion. GPE contains polymers, lithium salts, and liquid electrolyte, and inorganic nanoparticles are often used as fillers to improve electrochemical performance. However, such composite polymer electrolytes are usually prepared by means of blending, which can impact on the compatibility between the polymer and filler. In this study, the hybrid copolymer poly (organic palygorskite-co-methyl methacrylate) (poly(OPal-MMA)) is synthesized using organic palygorskite (OPal) and MMA as raw materials. The poly(OPal-MMA) gel electrolyte exhibits an ionic conductivity of 2.94 × 10-3 S/cm at 30 °C. The Li/poly(OPal-MMA) electrolyte/LiFePO4 cell shows a wide electrochemical window (approximately 4.7 V), high discharge capacity (146.36 mAh/g), and a low capacity-decay rate (0.02%/cycle).

10.
ACS Appl Mater Interfaces ; 10(7): 6785-6792, 2018 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-29388421

RESUMO

Electrorheological (ER) fluids are considered as a type of smart fluids because their rheological characteristics can be altered through an electric field. The discovery of giant ER effect revived the researchers' interest in the ER technological area. However, the poor stability including the insufficient dynamic shear stress, the large leakage current density, and the sedimentation tendency still hinders their practical applications. Herein, we report a facile and scalable coprecipitation method for synthesizing surfactant-free tin titanyl oxalate (TTO) particles with tremella-like wrinkly microstructure (W-TTO). The W-TTO-based ER fluids exhibit enhanced ER activity compared to that of the pristine TTO because of the improved wettability between W-TTO and the silicone oil. In addition, the static yield stress and leakage current of W-TTO ER fluids also show a fine time stability during the 30 day tests. More importantly, the dynamic shear stress of W-TTO ER fluids can remain stable throughout the shear rate range, which is valuable for their use in engineering applications. The results in this work provided a promising strategy to solving the long-standing problem of ER fluid stability. Moreover, this convenient route of synthesis may be considered a green approach for the mass production of giant ER materials.

11.
Pak J Pharm Sci ; 31(6(Special)): 2909-2913, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30630808

RESUMO

The objective of present study was to compare the effect of propofol and sevoflurane on cognitive function among elderly patients undergoing elective surgery under anesthesia. Elderly patient who met eligibility criteria were randomized to receive Intravenous anesthetic (propofol) or Inhalation anesthetic (sevoflurane, Group II) in allocation ratio of 1:1. The following variables were assessed, 1) recovery time; 2) measurement of attention and psychomotor functions; 3) memory (verbal memory); 4) obvious memories during anesthesia assessed by remembrance (recall) and recognition tests. A total of 200 patients were completed study. Statistical analysis showed that the recovery time was significantly greater in patients who received sevoflurane when compared to patients who received propofol (p<0.005). Patients who had treated with sevoflurane had greater reaction time compared to the patients who had been treated with propofol after 30- minutes of anesthesia (immediate test) [p<0.005]. Similar trend of results was observed between both the groups after 120 minutes of anesthesia (delayed test). Moreover, the patients who were treated with propofol had better memory score as compared to patients treated with sevoflurane. The difference was statistically significant between both the treatment groups in both type of recognition test (immediate and delayed recognition test) [p<0.005].


Assuntos
Cognição/efeitos dos fármacos , Procedimentos Cirúrgicos Eletivos/psicologia , Propofol/efeitos adversos , Sevoflurano/efeitos adversos , Idoso , Anestesia , Período de Recuperação da Anestesia , Anestésicos Inalatórios/efeitos adversos , Anestésicos Intravenosos/efeitos adversos , Atenção/efeitos dos fármacos , Feminino , Humanos , Masculino , Memória/efeitos dos fármacos , Rememoração Mental/efeitos dos fármacos , Projetos Piloto , Propofol/administração & dosagem , Desempenho Psicomotor/efeitos dos fármacos , Sevoflurano/administração & dosagem
12.
Polymers (Basel) ; 10(7)2018 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-30960627

RESUMO

Cellulose-based superabsorbent was synthesized by bacterial cellulose (BC) grafting acrylic acid (AA) in the presence of N,N'-methylenebisacrylamide (NMBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The influence of different factors on composite synthesis, including the weight ratio of the monomer to BC, initiator content, crosslinker content, AA neutralization degree, reaction temperature, and reaction time on the water absorbency of the composite, were systematically learned. Under the optimized conditions, the maximum water absorbency of the composite was 322 ± 23 g/g distilled water. However, the water absorbency was much less for the different salt solutions and the absorption capacity of the composite decreased as the concentration of the salt solutions increased. The pH value had a significant influence on water absorption performance, and with the increase of temperature, the water retention rate of the composite decreased. Additionally, the structure of this composite was characterized with nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results of NMR and FT-IR provided evidence that the composite was synthesized by BC and AA, and the microstructure showed that it had good performance for water absorption. In addition, the composite possessed suitable thermal stability, and that it could be used in a few high-temperature environments. Overall, this composite is promising for application in water absorption.

13.
Polymers (Basel) ; 10(11)2018 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-30961209

RESUMO

Bacterial cellulose (BC) is a new kind of cellulose with great potential in enhancing preparation of isotactic Polypropylene (iPP) composites, which have been found with excellent performance. However, the interface compatibility between BC and iPP is poor. In this study, iPP/BC composites were prepared by solution mixing. Esterification modified BC (CO) and Maleic anhydride grafted polypropylene (MAPP) added as a compatibilizer was both used to improve the interfacial compatibility of the iPP/BC composites. The rheology and isothermal crystallization behavior of the composites was tested and discussed. The result shows that the complex viscosity and storage modulus of the composite significantly increase in the rule iPP, iPP/BC2, iPP/CO2, and M-iPP/BC3, which indicates that the compatibility of the composite increases as this rule. According to the isothermal crystallization kinetics result, the crystal growth mode of iPP was not affected by the addition of BC and the interfacial compatibility. The spherulite growth rate of the iPP/BC composite increases with increasing crystallization temperature. Especially, the value decreases as the same rule with the complex viscosity and storage modulus of the composite at the same isothermal crystallization temperature. These results suggest that the interface compatibility of iPP/BC composites is greatly improved and the interface compatibility of the M-iPP/BC3 is better than the iPP/CO2.

14.
J Agric Food Chem ; 65(51): 11237-11242, 2017 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-29200277

RESUMO

In this study, a fast startup of semi-pilot-scale anaerobic digestion of food waste acid hydrolysate for biogas production was carried out for the first time. During the period of fast startup, more than 85% of chemical oxygen demand (COD) can be degraded, and even more than 90% of COD can be degraded during the later stage of anaerobic digestion. During this anaerobic digestion process, the biogas yield, the methane yield, and the CH4 content in biogas were 0.542 ± 0.056 m3/kgCOD consumption, 0.442 ± 0.053 m3/kgCOD consumption, and 81.52 ± 3.05%, respectively, and these values were high and stable. Besides, the fermentation pH was very stable, in which no acidification was observed during the anaerobic digestion process (outlet pH was 7.26 ± 0.05 for the whole anaerobic digestion). Overall, the startup of this anaerobic digestion can be completed in a short period (the system can be stable 2 days after the substrate was pumped into the bioreactor), and anaerobic digestion of food waste acid hydrolysate is feasible and attractive for industrial treatment of food waste and biogas production.


Assuntos
Biocombustíveis/análise , Metano/análise , Resíduos/análise , Anaerobiose , Reatores Biológicos , Projetos Piloto , Esgotos/química
15.
Indian J Microbiol ; 57(4): 393-399, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29151639

RESUMO

Durian is one important tropical fruit with high nutritional value, but its shell is usually useless and considered as waste. To explore the efficient and high-value utilization of this agricultural and food waste, in this study, durian shell was simply hydrolyzed by dilute sulfuric acid, and the durian shell hydrolysate after detoxification was used for bacterial cellulose (BC) production by Gluconacetobacter xylinus for the first time. BC was synthesized in static culture for 10 days and the highest BC yield (2.67 g/L) was obtained at the 8th day. The typical carbon sources in the substrate including glucose, xylose, formic acid, acetic acid, etc. can be utilized by G. xylinus. The highest chemical oxygen demand (COD) removal (16.40%) was obtained at the 8th day. The highest BC yield on COD consumption and the highest BC yield on sugar consumption were 93.51% and 22.98% (w/w), respectively, suggesting this is one efficient bioconversion for BC production. Durian shell hydrolysate showed small influence on the BC structure by comparison with the structure of BC generated in traditional Hestrin-Schramm medium detected by FE-SEM, FTIR, and XRD. Overall, this technology can both solve the issue of waste durian shell and produce valuable bio-polymer (BC).

16.
Prep Biochem Biotechnol ; 47(10): 1025-1031, 2017 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-28857665

RESUMO

Biomass acid hydrolysate of oleaginous yeast Trichosporon cutaneum after microbial oil extraction was applied as substrate for bacterial cellulose (BC) production by Komagataeibacter xylinus (also named as Gluconacetobacter xylinus previously) for the first time. BC was synthesized in static culture for 10 days, and the maximum BC yield (2.9 g/L) was got at the 4th day of fermentation. Most carbon sources in the substrate (glucose, mannose, formic acid, acetic acid) can be utilized by K. xylinus. The highest chemical oxygen demand (COD) removal (40.7 ± 3.0%) was obtained at the 6th day of fermentation, and then the COD increased possibly due to the degradation of BC. The highest BC yield on COD consumption was 38.7 ± 4.0% (w/w), suggesting that this is one efficient bioconversion for BC production. The BC structure was affected little by the substrate by comparison with that generated in classical HS medium using field-emission scanning electron microscope (FE-SEM), Fourier transform infrared, and X-ray diffraction. Overall, this technology can both solve the issue of waste oleaginous yeast biomass and produce valuable biopolymer (BC).


Assuntos
Biomassa , Celulose/metabolismo , Gluconacetobacter xylinus/metabolismo , Microbiologia Industrial/métodos , Óleos/isolamento & purificação , Trichosporon/metabolismo , Ácidos/metabolismo , Análise da Demanda Biológica de Oxigênio , Fermentação , Hidrólise , Óleos/metabolismo , Resíduos Sólidos/análise , Trichosporon/química
17.
Carbohydr Polym ; 175: 199-206, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28917857

RESUMO

Understanding the interaction mechanisms between xylan and xylan-degrading enzymes is beneficial to the efficient hydrolysis of xylan. Xylan from sugarcane bagasse (SB) was extracted and characterized. The effects of heat treatment and removal of side chains of SB xylan on the hydrolytic efficiency and synergistic action of endo-ß-1,4-xylanases (HoXyn11A and AnXyn10C), ß-xylosidases (AnXln3D), and α-l-arabinofuranosidases (AnAxh62A) were investigated. Results indicated that heat treatment of xylan can improve the hydrolytic efficiency of xylan-degrading enzymes, and it is essential for the efficient hydrolysis of xylan by HoXyn11A. The removal of arabinofuranosyl side chains of xylan by AnAxh62A before enzymatic hydrolysis reduced the hydrolytic efficiency of HoXyn11A and AnXyn10C on xylan. AnXyn10C was more efficient than HoXyn11A in hydrolysis of xylan, whereas HoXyn11A showed better synergistic action than AnXyn10C with AnAxh62A and AnXln3D in the hydrolysis of xylan. This study provides new insights on the enzymatic hydrolysis of SB into monosaccharides and xylo-oligosaccharides.


Assuntos
Celulose/química , Endo-1,4-beta-Xilanases/metabolismo , Saccharum/química , Xilanos/metabolismo , Hidrólise
18.
Prep Biochem Biotechnol ; 47(9): 860-866, 2017 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-28636483

RESUMO

Lumping kinetics models were built for the biological treatment of acetone-butanol-ethanol (ABE) fermentation wastewater by oleaginous yeast Trichosporon cutaneum with different fermentation temperatures. Compared with high temperature (33°C, 306 K) and low temperature (23°C, 296 K), medium temperature (28°C, 301 K) was beneficial for the cell growth and chemical oxygen demand (COD) degradation during the early stage of fermentation but the final yeast biomass and COD removal were influenced little. By lumping method, the materials in the bioconversion network were divided into five lumps (COD, lipid, polysaccharide, other intracellular products, other extracellular products), and the nine rate constants (k1-k9) for the models can well explain the bioconversion laws. The Gibbs free energy (G) for this bioconversion was positive, showing that it cannot happen spontaneous, but the existence of yeast can after the chemical equilibrium and make the bioconversion to be possible. Overall, the possibility of using lumping kinetics for elucidating the laws of materials conversion in the biological treatment of ABE fermentation wastewater by T. cutaneum has been initially proved and this method has great potential for further application.


Assuntos
Acetona/metabolismo , Butanóis/metabolismo , Etanol/metabolismo , Trichosporon/fisiologia , Águas Residuárias/microbiologia , Análise da Demanda Biológica de Oxigênio , Fermentação , Cinética , Metabolismo dos Lipídeos
19.
Biotechnol Biofuels ; 10: 147, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28616071

RESUMO

BACKGROUND: Microbial oil is one important bio-product for its important function in energy, chemical, and food industry. Finding suitable substrates is one key issue for its industrial application. Both hydrophilic and hydrophobic substrates can be utilized by oleaginous microorganisms with two different bio-pathways ("de novo" lipid fermentation and "ex novo" lipid fermentation). To date, most of the research on lipid fermentation has focused mainly on only one fermentation pathway and little work was carried out on both "de novo" and "ex novo" lipid fermentation simultaneously; thus, the advantages of both lipid fermentation cannot be fulfilled comprehensively. RESULTS: In this study, corncob acid hydrolysate with soybean oil was used as a mix-medium for combined "de novo" and "ex novo" lipid fermentation by oleaginous yeast Trichosporon dermatis. Both hydrophilic and hydrophobic substrates (sugars and soybean oil) in the medium can be utilized simultaneously and efficiently by T. dermatis. Different fermentation modes were compared and the batch mode was the most suitable for the combined fermentation. The influence of soybean oil concentration, inoculum size, and initial pH on the lipid fermentation was evaluated and 20 g/L soybean oil, 5% inoculum size, and initial pH 6.0 were suitable for this bioprocess. By this technology, the lipid composition of extracellular hydrophobic substrate (soybean oil) can be modified. Although adding emulsifier showed little beneficial effect on lipid production, it can modify the intracellular lipid composition of T. dermatis. CONCLUSIONS: The present study proves the potential and possibility of combined "de novo" and "ex novo" lipid fermentation. This technology can use hydrophilic and hydrophobic sustainable bio-resources to generate lipid feedstock for the production of biodiesel or other lipid-based chemical compounds and to treat some special wastes such as oil-containing wastewater.

20.
Bioresour Technol ; 232: 398-407, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28258805

RESUMO

Recently, technology of using oleaginous microorganisms for biological treatment of wastewaters has become one hot topic in biochemical and environmental engineering for its advantages such as easy for operation in basic bioreactor, having potential to produce valuable bio-products, efficient wastewaters treatment in short period, etc. To promote its industrialization, this article provides some comprehensive analysis of this technology such as its advances, issues, and outlook especially from industrial viewpoint. In detail, the types of wastewaters can be treated and the kinds of oleaginous microorganisms used for biological treatment are introduced, the potential of industrial application and issues (relatively low COD removal, low lipid yield, cost of operation, and lack of scale up application) of this technology are presented, and some critical outlook mainly on co-culture method, combination with other treatments, process controlling and adjusting are discussed systematically. By this article, some important information to develop this technology can be obtained.


Assuntos
Indústrias , Óleos/metabolismo , Águas Residuárias/microbiologia , Purificação da Água/métodos , Biodegradação Ambiental , Biotecnologia , Purificação da Água/economia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA