scholarly journals Ethylic Esters as Green Solvents for the Extraction of Intracellular Polyhydroxyalkanoates Produced by Mixed Microbial Culture

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2789
Author(s):  
Sara Alfano ◽  
Laura Lorini ◽  
Mauro Majone ◽  
Fabio Sciubba ◽  
Francesco Valentino ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Volatile Fatty Acids ◽  
Raw Materials ◽  
Systematic Investigation ◽  
Microbial Culture ◽  
Extraction Temperature ◽  
Green Solvents ◽  
Mixed Microbial Culture ◽  
Polymer Fractionation ◽  
Lower Temperature

Volatile fatty acids obtained from the fermentation of the organic fraction of municipal solid waste can be used as raw materials for non-toxic ethyl ester (EE) synthesis as well as feedstock for the production of polyhydroxyalkanoates (PHAs). Taking advantage of the concept of an integrated process of a bio-refinery, in the present paper, a systematic investigation on the extraction of intracellular poly(3-hydroxybutyrate-co-3-hydroxyvalerate), produced by mixed microbial culture by using EEs was reported. Among the tested EEs, ethyl acetate (EA) was the best solvent, dissolving the copolymer at the lowest temperature. Then, extraction experiments were carried out by EA at different temperatures on two biomass samples containing PHAs with different average molecular weights. The parallel characterization of the extracted and non-extracted PHAs evidenced that at the lower temperature (100 °C) EA solubilizes preferentially the polymer fractions richer in 3HV comonomers and with the lower molecular weight. By increasing the extraction temperature from 100 °C to 125 °C, an increase of recovery from about 50 to 80 wt% and a molecular weight reduction from 48% to 65% was observed. The results highlighted that the extracted polymer purity is always above 90 wt% and that it is possible to choose the proper extraction condition to maximize the recovery yield at the expense of polymer fractionation and degradation at high temperatures or use milder conditions to maintain the original properties of a polymer.

Intracellular biopolymer productions using mixed microbial cultures from fermented POME

2007 ◽  
Vol 56 (8) ◽  
pp. 179-185 ◽  
Author(s):  
Salmiati ◽  
Z. Ujang ◽  
M.R. Salim ◽  
M.F. Md Din ◽  
M.A. Ahmad
Keyword(s):  
Continuous Flow ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
High Volume ◽  
Microbial Culture ◽  
Mixed Microbial Culture ◽  
Bacterial Cultures ◽  
Mixed Microbial Cultures ◽  
Palm Oil Mill ◽  
And Performance

This study aimed to produce polyhydroxyalkanoates (PHAs) from organic wastes by mixed bacterial cultures using anaerobic-aerobic fermentation systems. Palm oil mill effluent (POME) was used as an organic source, which was cultivated in a two-step-process of acidogenesis and acid polymerization. POME was operated in a continuous flow anaerobic reactor to access volatile fatty acids (VFAs) for PHAs production. During fermentation, VFA concentration was produced in the range of 5 to 8 g/L and the COD concentration reduced up to 80% from 65 g/L. The VFA from anaerobic fermentation was then utilised for PHA production using a mixed culture in availability of aerobic bioreactor. Production of PHAs was recorded high when using a high volume of substrates because of the higher VFA concentration. Even though the maximum PHA content was observed at only 40% of the cell dried weight (CDW), their production and performance are significant in mixed microbial culture.

scholarly journals DEVELOPMENT OF METHODS FOR OBTAINING POLYSACCHARIDES FROM BIRCH LEAVES (BETULA PENDU-LA ROTH., BETULA PUBESCENS EHRH.)

2019 ◽  
pp. 23-31
Author(s):  
Kseniya Igorevna Rovkina ◽  
Sergey Vladimirovich Krivoshchekov ◽  
Artem Mikhaylovich Guriev ◽  
Mekhman Suleyman ogly Yusubov ◽  
Mikhail Valer'yevich Belousov
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Raw Materials ◽  
Gravimetric Method ◽  
Betula Pubescens ◽  
High Yield ◽  
Low Molecular Weight ◽  
Extraction Temperature ◽  
Extraction And Purification ◽  
Betula Pubescens Ehrh

The development of a complex technique for the extraction and purification of polysaccharides from birch leaves (Betula pendula Roth.,Betula pubescens Ehrh.) (PSfB) was the purpose of this study. The following characteristics were used as criteria for evaluating the effect of the parameters studied on the production of target substances: yield of PSfB (gravimetric method), protein content (spectrophotometric method), molecular weight distribution (high performance exclusion chromatography) and degree of purification from low molecular weight impurities (LMWI) (IR) spectroscopy).During the experiment, the optimal parameters were determined at various stages of obtaining the PSfB: degree of raw materials grinding – 1.2–3 mm, pH of the extractant (purified water with pH=7), the ratio of raw materials : extractant (1 : 20), extraction temperature (50 °C), temperature and degree of evaporation (50 °C; 4 times), the ratio of concentrate : ethanol (1 : 3) and the method of purification from the LMWI (ultrafiltration).The result of this work is an optimized method for obtaining PSfB, allowing to achieve high yield without loss of product quality (minimum allowable content of low molecular weight impurities with the highest content of high molecular weight fractions).This technique is the basis for the development of laboratory regulations for obtaining an active pharmaceutical substance based on polysaccharides from birch leaves.

Dynamic metabolic modelling of volatile fatty acids conversion to polyhydroxyalkanoates by a mixed microbial culture

2014 ◽  
Vol 31 (4) ◽  
pp. 335-344 ◽  
Author(s):  
Filipa Pardelha ◽  
Maria G.E. Albuquerque ◽  
Maria A.M. Reis ◽  
Rui Oliveira ◽  
João M.L. Dias
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Microbial Culture ◽  
Mixed Microbial Culture ◽  
Metabolic Modelling

Characterization of Nostoc muscorum NCCU-442 Derived Poly-3- hydroxybutyrate (PHB) and Polyethylene Glycol (PEG) Blends

2020 ◽  
Vol 10 (3) ◽  
pp. 200-207
Author(s):  
Sabbir Ansari ◽  
Tasneem Fatma
Keyword(s):  
Thermal Properties ◽  
Polyethylene Glycol ◽  
Morphological Properties ◽  
Morphological Alteration ◽  
Nostoc Muscorum ◽  
Microbial Culture ◽  
Polymer Science ◽  
Mixed Microbial Culture ◽  
Scanning Calorimetry ◽  
Casting Technique

Background: Poly-3-hydroxybutyrate (PHB) has attracted much consideration as biodegradable biocompatible polymer. This thermoplastic polymer has comparable material properties to polypropylene. Materials with more valuable properties may result from blending, a common practice in polymer science. Objective: In this paper, blends of PHB (extracted from cyanobacterium Nostoc muscorum NCCU- 442 with polyethylene glycol (PEG) were investigated for their thermal, tensile, hydrophilic and biodegradation properties. Methods: Blends were prepared in different proportions of PHB/PEG viz. 100/0, 98/2, 95/5, 90/10, 80/20, and 70/30 (wt %) using solvent casting technique. Morphological properties were investigated by using Scanning Electron Microscopy (SEM). Differential scanning calorimetry and thermogravimetric analysis were done for thermal properties determination whereas the mechanical and hydrophilic properties of the blends were studied by means of an automated material testing system and contact angle analyser respectively. Biodegradability potential of the blended films was tested as percent weight loss by mixed microbial culture within 60 days. Results: The blends showed good misciblity between PEG and PHB, however increasing concentrations of plasticizer caused morphological alteration as evidenced by SEM micrographs. PEG addition (10 % and above) showed significant alternations in the thermal properties of the blends. Increase in the PEG content increased the elongation at break ratio i.e enhanced the required plasticity of PHB. Rate of microbial facilitated degradation of the blends was greater with increasing PEG concentrations. Conclusion: Blending with PEG increased the crucial polymeric properties of cyanobacterial PHB.

Kinetics of growth and multi substrate degradation by an indigenous mixed microbial culture isolated from a wastewater treatment plant in Guwahati, India

2008 ◽  
Vol 58 (5) ◽  
pp. 1101-1106
Author(s):  
Pichiah Saravanan ◽  
K. Pakshirajan ◽  
P. K. Saha
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Lag Phase ◽  
Microbial Culture ◽  
High Concentration ◽  
Mixed Microbial Culture ◽  
Phenol Biodegradation ◽  
Low Concentration ◽  
Culture Growth

An indigenous mixed culture of microorganisms, isolated from a sewage treatment plant, was investigated for its potential to simultaneously degrade phenol and m-cresol during its growth in batch shake flasks. 22 full factorial designs with the two substrates as the factors, at two different levels and two different initial concentration ranges, were employed to carry out the biodegradation experiments. For complete utilisation of phenol and m-cresol, the culture took a minimum duration of 21 hrs at their low concentration of 100 mg/L each, and a maximum duration of 187 hrs at high concentration of 600 mg/L each in the multisubstrate system. The biodegradation results also showed that the presence of phenol in low concentration range (100–300 mg/L did not inhibit m-cresol biodegradation; on the other hand, presence of m-cresol inhibited phenol biodegradation by the culture. Moreover, irrespective of the concentrations used, phenol was degraded preferentially and earlier than m-cresol. During the culture growth, a lag phase was observed above a combined concentration of 500 mg/L i.e., 200 mg/L m-cresol and 300 mg/L of phenol and above). Statistical analysis of the specific growth rate of the culture in the multisubstrate system was also performed in the form of ANOVA and Student ‘t’ test, which gave good interpretation in terms of main and interaction effects of the substrates.

Preparation of n-Alkylacrylate and Vinyl Acetate Copolymer and Its Influence on Low-Temperature Fluidity of Diesel Fuel

2011 ◽  
Vol 236-238 ◽  
pp. 708-714 ◽  
Author(s):  
Hong An ◽  
Shu Gang Gao ◽  
Shuang Li ◽  
Yan Xin Xie
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
Vinyl Acetate ◽  
Diesel Fuel ◽  
Mass Fraction ◽  
Raw Materials ◽  
Cold Filter Plugging Point ◽  
Point Depressant ◽  
Petrochemical Company ◽  
Acetate Copolymer

The n-tetradecylacrylate-vinyl acetate copolymer (PPV) was prepared from n-tetradecylacrylate and vinyl acetate. The PPV was employed as pour point depressant to improve the low-temperature fluidity of the -20# diesel from Daqing Petrochemical Company. The result indicated that the solidification (SP) and the cold filter plugging point (CFPP) were affected largely by PPV. And when mass fraction of PPV -14(copolymerization conditions: 80 °C,w（benzoyl peroxide）1％（total weight of raw materials）, n（vinyl acetate）∶n（n- tetradecanolacrylate） = 4∶1 ) in diesel fuel was 0.1%wt, the SP reduced by 15.0 °C, the CFPP reduced by 6.0 °C simultaneously; We analysise the different molecular weight of PPV-14, and discover that the molecular weight of PPV-14 is ralated to the the low-temperature fluidity of the -20# diesel from Daqing Petrochemical Company. When mass fraction of PPV -14(molecular weight is 15000, distribution coefficient is 3.11) in diesel fuel was 0.1% wt, the SP reduced by 18.0 °C, the CFPP reduced by 7.0 °C, simultaneously.

Probing the molecular weights of sweetgum and pine kraft lignin fractions

TAPPI Journal ◽  
2021 ◽  
Vol 20 (6) ◽  
pp. 381-391
Author(s):  
JULIANA M. JARDIM ◽  
PETER W. HART ◽  
LUCIAN LUCIA ◽  
HASAN JAMEEL
Keyword(s):  
Molecular Weight ◽  
Black Liquor ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Systematic Investigation ◽  
Kraft Pulping ◽  
Molecular Weights ◽  
Lignin Recovery ◽  
Lignin Reactivity ◽  
Kinetics Of

The present investigation undertook a systematic investigation of the molecular weight (MW) of kraft lignins throughout the pulping process to establish a correlation between MW and lignin recovery at different extents of the kraft pulping process. The evaluation of MW is crucial for lignin characterization and utilization, since it is known to influence the kinetics of lignin reactivity and its resultant physicochemical properties. Sweetgum and pine lignins precipitated from black liquor at different pHs (9.5 and 2.5) and different extents of kraft pulping (30–150 min) were the subject of this effort. Gel permeation chromatography (GPC) was used to deter- mine the number average molecular weight (Mn), mass average molecular weight (Mw), and polydispersity of the lignin samples. It was shown that the MW of lignins from both feedstocks follow gel degradation theory; that is, at the onset of the kraft pulping process low molecular weightlignins were obtained, and as pulping progressed, the molecular weight peaked and subsequently decreased. An important finding was that acetobromination was shown to be a more effective derivatization technique for carbohydrates containing lignins than acetylation, the technique typically used for derivatization of lignin.

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