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Direct ethanol production from cellulose by consortium of Trichoderma reesei and Candida molischiana

  • Yingjie Bu , Bassam Alkotaini , Bipinchandra K. Salunke , Aarti R. Deshmukh , Pathikrit Saha and Beom Soo Kim EMAIL logo
Published/Copyright: May 18, 2019
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Green Processing and Synthesis
From the journal Green Processing and Synthesis Volume 8 Issue 1

Abstract

Industrial cellulosic ethanol production is a challenge due to the high cost of cellulases for hydrolysis when lignocellulosic materials are used as feedstock. In this study, direct ethanol production from cellulose was performed by consortium of Trichoderma reesei and Candida molischiana. Cellulose was hydrolyzed by a fully enzymatic saccharification process using Trichoderma reesei cellulases. The produced reducing sugar was further utilized by Candida molischiana for ethanol production. Because the optimal temperature for the cellulase system is approximately 50°C, the effect of temperature rise from 30°C to 50°C on cellulose hydrolysis was investigated. The results showed that the temperature rise from 30°C to 50°C after 36 h of cultivation was the best for reducing sugar and glucose production. Under these conditions, the maximum concentrations of reducing sugar and glucose produced by T. reesei were 8.0 g/L and 4.6 g/L at 60 h, respectively. The maximum production of ethanol by C. molischiana was 3.0 g/L after 120 h.

Keywords: bioethanol; Candida molischiana; cellulose hydrolysis; Trichoderma reesei

1 Introduction

The ongoing global dependence on fossil fuels has produced serious energy crises and environmental problems. Renewable energy sources such as organic waste are attractive alternatives to fossil fuels 1. New technologies to convert plant biomass into alternative biofuels, such as bioethanol, are being developed 2. Fermentation-derived ethanol can be produced from sugar, starch, or lignocellulosic biomass. Sugar and starch-based feedstocks are currently predominant at the industrial level and are economically advantageous 3. Lignocellulosic materials are important for the production of bioethanol due to their abundance 4. Industrial cellulosic ethanol production is still a challenge because of the high processing cost, for example, the high cost of cellulase for hydrolysis after using lignocellulosic materials as feedstock [5, 6, 7,]. During enzymatic hydrolysis, cellulase converts cellulose into soluble sugars.

Cellulose is a linear polymer of glucose units, which are hydrolyzed by endoglucanase, cellobiohydrolase, and β-glucosidases [8, 9,]. Some fungal strains produce large amounts of cellulase. For more than five decades, different Trichoderma reesei strains have been screened for their potential production of cellulases 9. T. reesei cellulases are widely used to hydrolyze lignocellulosic biomass to fermentable sugars. These enzymes synergistically convert cellulose because the action of one enzyme is utilized as a substrate by another enzyme, which leads to the production of glucose 10.

The existing ethanol production process includes a pretreatment step in which the sugar in the raw material is separated and fed to the fermenter as a substrate. Candida molischiana is one of the few yeast species capable of degrading cellobiose into glucose 11. Because C. molischiana is highly resistant to ethanol and heat, this yeast is likely to be more effective when introduced in industrial cellulose ethanol plants 12. One mutant strain of C. molischiana could tolerate up to 4% ethanol in the medium when grown at 45°C for 48 h 12. Recently, the highly efficient biodegradation of cellulosic biomass through microbial co-cultures or complex communities has been proposed 4. In this study, T. reesei and C. molischiana were sequentially cultured to produce ethanol from cellulose without acidic, ionic, or chemical pretreatments. First, the effect of temperature changes on cellulosic hydrolysis by T. reesei from 30°C to 50°C were investigated. The reducing sugars and glucose obtained were further used for ethanol production by C. molischiana to develop a fully enzymatic hydrolysis process from cellulose.

2 Materials and methods

2.1 Microorganisms

The fungus T. reesei RUT-C30 (KCTC 6968) and yeast C. molischiana (ATCC 2516) were purchased from Korean Collection for Type Cultures (Daejeon, Korea) and American Type Culture Collection (Manassas, VA, USA), respectively.

2.2 Media and cultivation

The T. reesei stock culture was aseptically grown on potato dextrose agar medium consisting of 24 g/L potato dextrose broth and 20 g/L agar and incubated at 30°C for 7 days until sporulation was sufficient. T. reesei was cultivated in chemically defined medium consisting of (per L): glucose 10 g, (NH4)2SO4 1.4 g, KH2PO4 2 g, CaCl2 0.3 g, MgSO4·7H2O 0.3 g, FeSO4·7H2O 5×10-2 g, MnSO4·5H2O 1.56×10-2 g, ZnSO4·7H2O 1.4×10-2 g, and CoCl2·6H2O 2×10-2 g. The pre-culture was incubated at 30°C and 175 rpm for 48 h. Next, 10 mL of the pre-culture was inoculated into 100 mL of the same chemically defined medium containing 10 to 30 g/L of α-cellulose (Sigma) instead of 10 g/L glucose in a 250 mL flask.

C. molischiana stock culture was cultivated in YM agar consisting of (per L): 3 g yeast extract, 3 g malt extract, 5 g peptone, 10 g glucose, and 20 g agar. It was incubated at 30°C for 2 days. C. molischiana was then inoculated into YM broth and grown in a shaking incubator at 30°C and 175 rpm for 48 h. For ethanol production, 10 mL of C. molischiana culture was added to 100 mL of T. reesei cultured medium in a 250 mL flask at 30°C after 60 h.

2.3 Effect of temperature rise time on cellulose hydrolysis

The cellulose hydrolysis process was optimized for temperature rise times (24 to 60 h). The temperature rise time refers to the period of cultivation at 30°C prior to increasing to 50°C for reducing sugar and glucose production. The initial pH was adjusted to 7 using 3 N NaOH. T. reesei was grown in a 250 mL flask with 100 mL of chemically defined medium containing cellulose.

2.4 Analytical methods

Reducing sugar was measured by the dinitrosalicylic acid (DNS) method as described previously 13. Glucose concentration was measured using an Asan set glucose kit (Asan Pharm, Co. Ltd., Seoul, Korea). Ethanol concentration was measured by HPLC system (YL 9100, Young-Lin, Inc., Anyang, Korea) using a Biorad Aminex hpx-87h column (Hercules, CA, USA) with a refractive index detector.

3 Results and discussion

Cellulases from T. reesei fungi have been used in the biofuels industry to degrade vegetable feedstocks into substrates that can be used for other processes. Another promising microorganism for bioethanol production is C. molischiana, which produces ethanol from substrates containing glucose, fructose, and sucrose 11. Glucose production using T. reesei RUT-C30 fermentation is a complex system 14. Many factors influence glucose productivity, including pre-incubation time, initial pH, and initial cellulosic concentration. In a preliminary study, fermentation was performed up to 5 days, and the production of reducing sugar and glucose was monitored at 24-h intervals. The optimal conditions for pre-culture incubation time, initial pH, and initial cellulosic concentration were 2 days, pH 7 and 20 g/L, respectively, in terms of reducing sugar and glucose production from cellulose. Under these conditions, the maximum reducing sugar and glucose production reached 4.1 and 2.6 g/L, respectively, after 2 days of incubation.

T. reesei RUT-C30 is an overproducer of cellulolytic enzymes, including cellulases and xylanases 14. Complete cellulose hydrolysis to glucose requires exoglucanases (also cellobiohydrolases), endoglucanases, and β-glucosidases. The extracellular cellulolytic system of T. reesei is composed of 60 to 80% cellobiohydrolases or exoglucanases, 20 to 36% endoglucanases, and 1% β-glucosidases, which act synergistically to convert cellulose to glucose 15. The optimal temperature for this cellulase system is approximately 50°C 16. Therefore, the effect of increasing the temperature from 30°C to 50°C on cellulose hydrolysis to produce reducing sugar and glucose was investigated at 24, 36, 48, and 60 h (Figure 1).

Figure 1 Time courses of cellulose hydrolysis by T. reesei to (a) reducing sugar production and (b) glucose production at different temperature rise times (24 to 60 h). The temperature rise time refers to the period of cultivation at 30°C prior to increasing to 50°C. For example, the 24 h temperature rise time means that T. reesei was first grown at 30°C and the temperature was risen to 50°C after 24 h. Control means constant temperature operation at 30°C (no temperature change).
Figure 1

Time courses of cellulose hydrolysis by T. reesei to (a) reducing sugar production and (b) glucose production at different temperature rise times (24 to 60 h). The temperature rise time refers to the period of cultivation at 30°C prior to increasing to 50°C. For example, the 24 h temperature rise time means that T. reesei was first grown at 30°C and the temperature was risen to 50°C after 24 h. Control means constant temperature operation at 30°C (no temperature change).

Figures 1A and 1B show changes in the production of reducing sugar and glucose over time when the temperature was increased to 50°C. At constant temperature at 30°C (control), the maximum reducing sugar and glucose production reached 4.1 and 2.7 g/L, respectively. Sugar production gradually increased at a temperature rise time of 24 to 36 h, while sugar production decreased at a temperature rise time of 48 to 60 h. When the temperature was increased at 36 h, the maximum reducing sugar and

glucose production reached 8.0 and 4.6 g/ L, respectively, which were 95% and 70% higher, respectively, than control. Thus, the incubation time of 36 h was used for further ethanol production experiments. Because 20 g/ L of initial cellulose was used, the total yields of reducing sugar and glucose from cellulose were 40% and 23%, respectively. This is higher than a previous report using carboxymethyl cellulose (CMC) as the carbon source and performed in T. reesei with a total yield of 25.7% reduction sugar 17.

The following optimized conditions were used for the conversion of cellulose into reducing sugar and glucose: pre-culture of T. reesei for 2 days, 10% (v/v) inoculum in cultivation medium, initial pH of 7, initial cellulose concentration of 20 g/L, and temperature rise from 30°C to 50°C at 36 h (Figure 2). After 72 h of T. reesei cultivation, the temperature was again lowered to 30°C, and C. molischiana was inoculated. The maximum ethanol concentration was 3.0 g/L at 120 h, resulting in a yield of 0.15 g of ethanol per g of cellulose. Considering that the maximum glucose production was 4.6 g/L at 60 h, the ethanol yield based on glucose (0.66 g of ethanol per g of glucose) was remarkably higher than the typical yield of 0.48 g of ethanol per g of glucose by Saccharomyces cerevisiae. This result reflects that C. molischiana utilizes cellodextrins as well as glucose. This yeast produces β-glucosidase that degrades cellobiose to glucose 11. C. molischiana ferments cellodextrins with degree of polymerization 2 to 6 to ethanol 18. The ability of this yeast to utilize cellulose degradation products for growth is advantageous for the production of lignocellulosic

Figure 2 Ethanol production from cellulose by consortium of T. reesei and C. molischiana. T. reesei was initially grown at 30°C and the temperature was risen to 50°C after 36 h. After 72h, the temperature was again lowered to 30°C, and C. molischiana was inoculated.
Figure 2

Ethanol production from cellulose by consortium of T. reesei and C. molischiana. T. reesei was initially grown at 30°C and the temperature was risen to 50°C after 36 h. After 72h, the temperature was again lowered to 30°C, and C. molischiana was inoculated.

ethanol because not only glucose but also cellobiose and cellodextrins can be used as substrates for ethanol production. It is noteworthy that C. molischiana can perform the fermentation in the presence of the T. reesei, suggesting that there are not sufficient detrimental enzymes such as chitinases that would contribute to detrimental effects on the yeast to prevent the alcohol accumulation. This sequential approach does not require that T. reesei have alcohol tolerance as would be required for a simultaneous co-culture.

Table 1 compares ethanol production from cellulosic substrates by consortium of microorganisms. High ethanol yields were obtained using metabolically engineered strains of Clostridium thermocellum and Thermoanaerobacterium saccharolyticum19 or by adding endoglucanase 20. The combination of Fusarium oxysporum and recombinant S. cerevisiae produced 4.5% ethanol from 110 g/L pretreated wheat straw 21. For wild-type strains, the ethanol yield (15%) obtained in this study is similar to or higher than previously reported. The co-culture of a hyper cellulase producer, Acremonium cellulolyticus C-1, and S. cerevisiae yielded 12 to 19% ethanol 22. A thermophilic anaerobic Clostridium sp. isolated from a Himalayan hot spring yielded 17% ethanol by co-culture with Thermoanaerobacter sp. from Avicel 23. The lower ethanol yield of 5.6% obtained by co-culture of T. reesei with Aspergillus niger and Zymmomonas mobilis from CMC 17 suggests that C. molischiana may have superior performance to Z. mobilis for ethanol production using some cellulose hydrolysates as carbon sources.

Table 1

Summary of ethanol production from cellulosic substrates by consortium of microorganisms.

ConsortiumSubstrateReducing Sugar Yield (%)aGlucose Yield (%)bEthanol Production Time (h)Ethanol Yield (%)cReferences
Acremonium cellulolyticus and Saccharomy- ces cerevisiaeSolka–Floc 50–300 g/L––7212–1922
Clostridium phytofermentans and Saccharo- myces cerevisiae cdt–1 with added endoglu- canaseα–Cellulose 100 g/L––4002220
Clostridium sp. and Thermoanaerobacter sp.Avicel 11.1 g/ L–––1723
Metabolically engineered Clostridium thermocellum and Thermoanaerobacterium saccharolyticumAvicel 92 g/L––1464119
Fusarium oxysporum and recombinant Saccharomyces cerevisiaePretreated wheat straw 110 g/L––484.521
Trichoderma reesei, Aspergillus niger and Zymmomonas mobilisCMC 10 g/L25.7–245.617
Trichoderma reesei and Candida molischianaα–Cellulose 20 g/L402312015This study

  1. a (g reducing sugar per g substrate supplied) × 100 (%)

    b (g glucose per g substrate supplied) × 100 (%)

    c (g ethanol per g substrate supplied) × 100 (%)

In summary, by increasing the temperature from 30°C to 50°C at 36 h for cellulose hydrolysis by T. reesei, reducing sugar and glucose production were improved by 95 and 70%, respectively, compared with no temperature rise. When the cellodextrin-utilizing yeast C. molischiana was inoculated at 60 h, the ethanol yield increased to 15% in 120 h. This study shows that direct ethanol production from cellulose may be possible by consortium of microorganisms when the hyper cellulose producer is available in a highly productive bioreactor mode of operation.

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Acknowledgments

This research was supported by the National Research Foundation of Korea (NRF-2017R1A2B4002371).

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Received: 2018-08-13
Accepted: 2018-10-09
Published Online: 2019-05-18
Published in Print: 2019-01-28

© 2019 Bu et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 Public License.

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  84. Microstructure and luminescence of VO2 (B) nanoparticle synthesis by hydrothermal method
  85. Optimization of uranium removal from uranium plant wastewater by response surface methodology (RSM)
  86. Microwave drying of nickel-containing residue: dielectric properties, kinetics, and energy aspects
  87. Simple and convenient two step synthesis of 5-bromo-2,3-dimethoxy-6-methyl-1,4-benzoquinone
  88. Biodiesel production from waste cooking oil
  89. The effect of activation temperature on structure and properties of blue coke-based activated carbon by CO2 activation
  90. Optimization of reaction parameters for the green synthesis of zero valent iron nanoparticles using pine tree needles
  91. Microwave-assisted protocol for squalene isolation and conversion from oil-deodoriser distillates
  92. Denitrification performance of rare earth tailings-based catalysts
  93. Facile synthesis of silver nanoparticles using Averrhoa bilimbi L and Plum extracts and investigation on the synergistic bioactivity using in vitro models
  94. Green production of AgNPs and their phytostimulatory impact
  95. Photocatalytic activity of Ag/Ni bi-metallic nanoparticles on textile dye removal
  96. Topical Issue: Green Process Engineering / Guest Editors: Martine Poux, Patrick Cognet
  97. Modelling and optimisation of oxidative desulphurisation of tyre-derived oil via central composite design approach
  98. CO2 sequestration by carbonation of olivine: a new process for optimal separation of the solids produced
  99. Organic carbonates synthesis improved by pervaporation for CO2 utilisation
  100. Production of starch nanoparticles through solvent-antisolvent precipitation in a spinning disc reactor
  101. A kinetic study of Zn halide/TBAB-catalysed fixation of CO2 with styrene oxide in propylene carbonate
  102. Topical on Green Process Engineering
https://doi.org/10.1515/gps-2019-0009
Keywords for this article
bioethanol; Candida molischiana; cellulose hydrolysis; Trichoderma reesei
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Articles in the same Issue

  1. Regular Articles
  2. Studies on the preparation and properties of biodegradable polyester from soybean oil
  3. Flow-mode biodiesel production from palm oil using a pressurized microwave reactor
  4. Reduction of free fatty acids in waste oil for biodiesel production by glycerolysis: investigation and optimization of process parameters
  5. Saccharin: a cheap and mild acidic agent for the synthesis of azo dyes via telescoped dediazotization
  6. Optimization of lipase-catalyzed synthesis of polyethylene glycol stearate in a solvent-free system
  7. Green synthesis of iron oxide nanoparticles using Platanus orientalis leaf extract for antifungal activity
  8. Ultrasound assisted chemical activation of peanut husk for copper removal
  9. Room temperature silanization of Fe3O4 for the preparation of phenyl functionalized magnetic adsorbent for dispersive solid phase extraction for the extraction of phthalates in water
  10. Evaluation of the saponin green extraction from Ziziphus spina-christi leaves using hydrothermal, microwave and Bain-Marie water bath heating methods
  11. Oxidation of dibenzothiophene using the heterogeneous catalyst of tungsten-based carbon nanotubes
  12. Calcined sodium silicate as an efficient and benign heterogeneous catalyst for the transesterification of natural lecithin to L-α-glycerophosphocholine
  13. Synergistic effect between CO2 and H2O2 on ethylbenzene oxidation catalyzed by carbon supported heteropolyanion catalysts
  14. Hydrocyanation of 2-arylmethyleneindan-1,3-diones using potassium hexacyanoferrate(II) as a nontoxic cyanating agent
  15. Green synthesis of hydratropic aldehyde from α-methylstyrene catalyzed by Al2O3-supported metal phthalocyanines
  16. Environmentally benign chemical recycling of polycarbonate wastes: comparison of micro- and nano-TiO2 solid support efficiencies
  17. Medicago polymorpha-mediated antibacterial silver nanoparticles in the reduction of methyl orange
  18. Production of value-added chemicals from esterification of waste glycerol over MCM-41 supported catalysts
  19. Green synthesis of zerovalent copper nanoparticles for efficient reduction of toxic azo dyes congo red and methyl orange
  20. Optimization of the biological synthesis of silver nanoparticles using Penicillium oxalicum GRS-1 and their antimicrobial effects against common food-borne pathogens
  21. Optimization of submerged fermentation conditions to overproduce bioethanol using two industrial and traditional Saccharomyces cerevisiae strains
  22. Extraction of In3+ and Fe3+ from sulfate solutions by using a 3D-printed “Y”-shaped microreactor
  23. Foliar-mediated Ag:ZnO nanophotocatalysts: green synthesis, characterization, pollutants degradation, and in vitro biocidal activity
  24. Green cyclic acetals production by glycerol etherification reaction with benzaldehyde using cationic acidic resin
  25. Biosynthesis, characterization and antimicrobial activities assessment of fabricated selenium nanoparticles using Pelargonium zonale leaf extract
  26. Synthesis of high surface area magnesia by using walnut shell as a template
  27. Controllable biosynthesis of silver nanoparticles using actinobacterial strains
  28. Green vegetation: a promising source of color dyes
  29. Mechano-chemical synthesis of ammonia and acetic acid from inorganic materials in water
  30. Green synthesis and structural characterization of novel N1-substituted 3,4-dihydropyrimidin-2(1H)-ones
  31. Biodiesel production from cotton oil using heterogeneous CaO catalysts from eggshells prepared at different calcination temperatures
  32. Regeneration of spent mercury catalyst for the treatment of dye wastewater by the microwave and ultrasonic spray-assisted method
  33. Green synthesis of the innovative super paramagnetic nanoparticles from the leaves extract of Fraxinus chinensis Roxb and their application for the decolourisation of toxic dyes
  34. Biogenic ZnO nanoparticles: a study of blueshift of optical band gap and photocatalytic degradation of reactive yellow 186 dye under direct sunlight
  35. Leached compounds from the extracts of pomegranate peel, green coconut shell, and karuvelam wood for the removal of hexavalent chromium
  36. Enhancement of molecular weight reduction of natural rubber in triphasic CO2/toluene/H2O systems with hydrogen peroxide for preparation of biobased polyurethanes
  37. An efficient green synthesis of novel 1H-imidazo[1,2-a]imidazole-3-amine and imidazo[2,1-c][1,2,4]triazole-5-amine derivatives via Strecker reaction under controlled microwave heating
  38. Evaluation of three different green fabrication methods for the synthesis of crystalline ZnO nanoparticles using Pelargonium zonale leaf extract
  39. A highly efficient and multifunctional biomass supporting Ag, Ni, and Cu nanoparticles through wetness impregnation for environmental remediation
  40. Simple one-pot green method for large-scale production of mesalamine, an anti-inflammatory agent
  41. Relationships between step and cumulative PMI and E-factors: implications on estimating material efficiency with respect to charting synthesis optimization strategies
  42. A comparative sorption study of Cr3+ and Cr6+ using mango peels: kinetic, equilibrium and thermodynamic
  43. Effects of acid hydrolysis waste liquid recycle on preparation of microcrystalline cellulose
  44. Use of deep eutectic solvents as catalyst: A mini-review
  45. Microwave-assisted synthesis of pyrrolidinone derivatives using 1,1’-butylenebis(3-sulfo-3H-imidazol-1-ium) chloride in ethylene glycol
  46. Green and eco-friendly synthesis of Co3O4 and Ag-Co3O4: Characterization and photo-catalytic activity
  47. Adsorption optimized of the coal-based material and application for cyanide wastewater treatment
  48. Aloe vera leaf extract mediated green synthesis of selenium nanoparticles and assessment of their In vitro antimicrobial activity against spoilage fungi and pathogenic bacteria strains
  49. Waste phenolic resin derived activated carbon by microwave-assisted KOH activation and application to dye wastewater treatment
  50. Direct ethanol production from cellulose by consortium of Trichoderma reesei and Candida molischiana
  51. Agricultural waste biomass-assisted nanostructures: Synthesis and application
  52. Biodiesel production from rubber seed oil using calcium oxide derived from eggshell as catalyst – optimization and modeling studies
  53. Study of fabrication of fully aqueous solution processed SnS quantum dot-sensitized solar cell
  54. Assessment of aqueous extract of Gypsophila aretioides for inhibitory effects on calcium carbonate formation
  55. An environmentally friendly acylation reaction of 2-methylnaphthalene in solvent-free condition in a micro-channel reactor
  56. Aegle marmelos phytochemical stabilized synthesis and characterization of ZnO nanoparticles and their role against agriculture and food pathogen
  57. A reactive coupling process for co-production of solketal and biodiesel
  58. Optimization of the asymmetric synthesis of (S)-1-phenylethanol using Ispir bean as whole-cell biocatalyst
  59. Synthesis of pyrazolopyridine and pyrazoloquinoline derivatives by one-pot, three-component reactions of arylglyoxals, 3-methyl-1-aryl-1H-pyrazol-5-amines and cyclic 1,3-dicarbonyl compounds in the presence of tetrapropylammonium bromide
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  61. Extraction of glycyrrhizic acid by aqueous two-phase system formed by PEG and two environmentally friendly organic acid salts - sodium citrate and sodium tartrate
  62. Green synthesis of copper oxide nanoparticles using Juglans regia leaf extract and assessment of their physico-chemical and biological properties
  63. Deep eutectic solvents (DESs) as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones
  64. Biosynthesis, characterization and anti-microbial activity of silver nanoparticle based gel hand wash
  65. Efficient and selective microwave-assisted O-methylation of phenolic compounds using tetramethylammonium hydroxide (TMAH)
  66. Anticoagulant, thrombolytic and antibacterial activities of Euphorbia acruensis latex-mediated bioengineered silver nanoparticles
  67. Volcanic ash as reusable catalyst in the green synthesis of 3H-1,5-benzodiazepines
  68. Green synthesis, anionic polymerization of 1,4-bis(methacryloyl)piperazine using Algerian clay as catalyst
  69. Selenium supplementation during fermentation with sugar beet molasses and Saccharomyces cerevisiae to increase bioethanol production
  70. Biosynthetic potential assessment of four food pathogenic bacteria in hydrothermally silver nanoparticles fabrication
  71. Investigating the effectiveness of classical and eco-friendly approaches for synthesis of dialdehydes from organic dihalides
  72. Pyrolysis of palm oil using zeolite catalyst and characterization of the boil-oil
  73. Azadirachta indica leaves extract assisted green synthesis of Ag-TiO2 for degradation of Methylene blue and Rhodamine B dyes in aqueous medium
  74. Synthesis of vitamin E succinate catalyzed by nano-SiO2 immobilized DMAP derivative in mixed solvent system
  75. Extraction of phytosterols from melon (Cucumis melo) seeds by supercritical CO2 as a clean technology
  76. Production of uronic acids by hydrothermolysis of pectin as a model substance for plant biomass waste
  77. Biofabrication of highly pure copper oxide nanoparticles using wheat seed extract and their catalytic activity: A mechanistic approach
  78. Intelligent modeling and optimization of emulsion aggregation method for producing green printing ink
  79. Improved removal of methylene blue on modified hierarchical zeolite Y: Achieved by a “destructive-constructive” method
  80. Two different facile and efficient approaches for the synthesis of various N-arylacetamides via N-acetylation of arylamines and straightforward one-pot reductive acetylation of nitroarenes promoted by recyclable CuFe2O4 nanoparticles in water
  81. Optimization of acid catalyzed esterification and mixed metal oxide catalyzed transesterification for biodiesel production from Moringa oleifera oil
  82. Kinetics and the fluidity of the stearic acid esters with different carbon backbones
  83. Aiming for a standardized protocol for preparing a process green synthesis report and for ranking multiple synthesis plans to a common target product
  84. Microstructure and luminescence of VO2 (B) nanoparticle synthesis by hydrothermal method
  85. Optimization of uranium removal from uranium plant wastewater by response surface methodology (RSM)
  86. Microwave drying of nickel-containing residue: dielectric properties, kinetics, and energy aspects
  87. Simple and convenient two step synthesis of 5-bromo-2,3-dimethoxy-6-methyl-1,4-benzoquinone
  88. Biodiesel production from waste cooking oil
  89. The effect of activation temperature on structure and properties of blue coke-based activated carbon by CO2 activation
  90. Optimization of reaction parameters for the green synthesis of zero valent iron nanoparticles using pine tree needles
  91. Microwave-assisted protocol for squalene isolation and conversion from oil-deodoriser distillates
  92. Denitrification performance of rare earth tailings-based catalysts
  93. Facile synthesis of silver nanoparticles using Averrhoa bilimbi L and Plum extracts and investigation on the synergistic bioactivity using in vitro models
  94. Green production of AgNPs and their phytostimulatory impact
  95. Photocatalytic activity of Ag/Ni bi-metallic nanoparticles on textile dye removal
  96. Topical Issue: Green Process Engineering / Guest Editors: Martine Poux, Patrick Cognet
  97. Modelling and optimisation of oxidative desulphurisation of tyre-derived oil via central composite design approach
  98. CO2 sequestration by carbonation of olivine: a new process for optimal separation of the solids produced
  99. Organic carbonates synthesis improved by pervaporation for CO2 utilisation
  100. Production of starch nanoparticles through solvent-antisolvent precipitation in a spinning disc reactor
  101. A kinetic study of Zn halide/TBAB-catalysed fixation of CO2 with styrene oxide in propylene carbonate
  102. Topical on Green Process Engineering
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