scholarly journals Assessment of Long-Term Fermentability of PHA-Based Materials from Pure and Mixed Microbial Cultures for Potential Environmental Applications

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 897
Author(s):  
Neda Amanat ◽  
Bruna Matturro ◽  
Marta Maria Rossi ◽  
Francesco Valentino ◽  
Marianna Villano ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Volatile Fatty Acids ◽  
Rapid Onset ◽  
Pilot Scale ◽  
Point Of View ◽  
Microbial Cultures ◽  
Extraction And Purification ◽  
Fermentation Pattern ◽  
Mixed Microbial Cultures

The use of polyhydroxyalkanoates (PHA) as slow-release electron donors for environmental remediation represents a novel and appealing application that is attracting considerable attention in the scientific community. In this context, here, the fermentation pattern of different types of PHA-based materials has been investigated in batch and continuous-flow experiments. Along with commercially available materials, produced from axenic microbial cultures, PHA produced at pilot scale by mixed microbial cultures (MMC) using waste feedstock have been also tested. As a main finding, a rapid onset of volatile fatty acids (VFA) production was observed with a low-purity MMC-deriving material, consisting of microbial cells containing 56% (on weight basis) of intracellular PHA. Indeed, with this material a sustained, long-term production of organic acids (i.e., acetic, propionic, and butyric acids) was observed. In addition, the obtained yield of conversion into acids (up to 70% gVFA/gPHA) was higher than that obtained with the other tested materials, made of extracted and purified PHA. These results clearly suggest the possibility to directly use the PHA-rich cells deriving from the MMC production process, with no need of extraction and purification procedures, as a sustainable and effective carbon source bringing remarkable advantages from an economic and environmental point of view.

Pilot-scale performance of PHA production from municipal solid waste using mixed microbial cultures (MMC)

2016 ◽  
Vol 33 ◽  
pp. S39-S40
Author(s):  
Francesco Valentino ◽  
Andrea Martinelli ◽  
Laura Lorini ◽  
Cleofe Palocci ◽  
Mauro Majone ◽  
...  
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Pilot Scale ◽  
Microbial Cultures ◽  
Mixed Microbial Cultures ◽  
Pha Production

scholarly journals From Food Waste to Volatile Fatty Acids towards a Circular Economy

2021 ◽  
Author(s):  
Mónica Carvalheira ◽  
Anouk F. Duque
Keyword(s):  
Fatty Acids ◽  
Food Waste ◽  
Circular Economy ◽  
Volatile Fatty Acids ◽  
Animal Feed ◽  
Anaerobic Fermentation ◽  
Industrial Sector ◽  
Added Value ◽  
Microbial Cultures ◽  
Mixed Microbial Cultures

The food industrial sector generates large amounts of waste, which are often used for animal feed, for agriculture or landfilled. However, these wastes have a very reach composition in carbon and other compounds, which make them very attractive for valorization through biotechnological processes. Added value compounds, such as volatile fatty acids (VFAs), can be produced by anaerobic fermentation using pure cultures or mixed microbial cultures and food waste as carbon source. Research on valuable applications for VFAs, such as polyhydroxyalkanoates, bioenergy or biological nutrient removal, towards a circular economy is emerging. This enhances the sustainability and the economic value of food waste. This chapter reviews the various types of food waste used for VFAs production using mixed microbial cultures, the anaerobic processes, involved and the main applications for the produced VFAs. The main parameters affecting VFAs production are also discussed.

scholarly journals Influence of the total concentration and the profile of volatile fatty acids on polyhydroxyalkanoates (PHA) production by mixed microbial cultures

2021 ◽  
Author(s):  
Gloria Bravo-Porras ◽  
Luis A. Fernández-Güelfo ◽  
Carlos J. Álvarez-Gallego ◽  
María Carbú ◽  
Diego Sales ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Total Concentration ◽  
Degradation Process ◽  
Microbial Cultures ◽  
Dry Cell Weight ◽  
Cheap Alternative ◽  
Mixed Microbial Cultures ◽  
Pha Production ◽  
Dry Cell

AbstractPolyhydroxyalkanoates (PHAs) production from lignocellulosic biomass using mixed microbial cultures (MMC) is a potential cheap alternative for reducing the use of petroleum-based plastics. In this study, an MMC adapted to acidogenic effluent from dark fermentation (DF) of exhausted sugar beet cossettes (ESBC) has been tested in order to determine its capability to produce PHAs from nine different synthetic mixtures of volatile fatty acids (VFAs). The tests consisted of mixtures of acetic, propionic, butyric, and valeric acids in the range of 1.5–9.0 g/L of total acidity and with three different valeric:butyric ratios (10:1, 1:1, and 1:10). Experimental results have shown a consistent preference of the MMC for the butyric and valeric acids as carbon source instead other shorter acids (propionic or acetic) in terms of PHA production yield (estimated in dry cell weight basis), with a maximum value of 23% w/w. Additionally, valeric-rich mixtures have demonstrated to carry out a fast degradation process but with poor final PHA production compared with high butyric mixtures. Finally, high initial butyric and valeric concentrations (1.1 g/L and 4.1 g/L) have demonstrated to be counterproductive to PHA production.

scholarly journals Optimization of Green Extraction and Purification of PHA Produced by Mixed Microbial Cultures from Sludge

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1185
Author(s):  
Guilherme A. de Souza Reis ◽  
Michiel H. A. Michels ◽  
Gabriela L. Fajardo ◽  
Ischa Lamot ◽  
Jappe H. de Best
Keyword(s):  
Municipal Wastewater ◽  
Dimethyl Carbonate ◽  
Small Difference ◽  
Municipal Wastewater Treatment ◽  
Microbial Cultures ◽  
Extraction And Purification ◽  
Significant Difference ◽  
Mixed Microbial Cultures ◽  
Visual Difference ◽  
Wastewater Treatment Systems

Sludge from municipal wastewater treatment systems can be used as a source of mixed microbial cultures for the production of polyhydroxyalkanoates (PHA). Stored intracellularly, the PHA is accumulated by some species of bacteria as energy stockpile and can be extracted from the cells by reflux extraction. Dimethyl carbonate was tested as a solvent for the PHA extraction at different extraction times and biomass to solvent ratios, and 1-butanol was tested for purifying the obtained PHA at different purification times and PHA to solvent ratios. Overall, only a very small difference was observed in the different extraction scenarios. An average extraction amount of 30.7 ± 1.6 g of PHA per 100 g of biomass was achieved. After purification with 1-butanol, a visual difference was observed in the PHA between the tested scenarios, although the actual purity of the resulting samples did not present a significant difference. The overall purity increased from 91.2 ± 0.1% to 98.0 ± 0.1%.

scholarly journals Bio-based conversion of volatile fatty acids from waste streams to polyhydroxyalkanoates using mixed microbial cultures

2021 ◽  
Vol 323 ◽  
pp. 124604
Author(s):  
Mariel Perez-Zabaleta ◽  
Merve Atasoy ◽  
Kasra Khatami ◽  
Elsa Eriksson ◽  
Zeynep Cetecioglu
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Waste Streams ◽  
Microbial Cultures ◽  
Mixed Microbial Cultures

Selective statistical estimates of multi-year monthly concentrations of biogenous pollution of small rivers of the Northwest zone of the Russian Federation

2020 ◽  
pp. 9-13
Author(s):  
Sergey Kovalenko
Keyword(s):  
Statistical Processing ◽  
Point Of View ◽  
Small Rivers ◽  
Statistical Parameters ◽  
Monthly Data ◽  
Statistical Estimates ◽  
Scientific Task ◽  
The Russian Federation ◽  
Agricultural Areas

The management of surface watercourses is an urgent scientific task. The article presents the results of statistical processing of long-term monthly data of field observations of hydrological and hydrochemical parameters along the Upper Yerga small river in the Vologda region. Sampling estimates of statistical parameters are obtained, autocorrelation and correlation analyzes are performed. The limiting periods from the point of view of pollution for water receivers receiving wastewater from drained agricultural areas are identified.

Masonry: the brittle or plastic material?

2019 ◽  
pp. 22-28
Keyword(s):  
Plastic Material ◽  
Experimental Studies ◽  
Point Of View ◽  
Plastic Properties ◽  
Plastic Deformations ◽  
Base Materials ◽  
Stress States ◽  
Creep Deformations ◽  
Structural Point

The results of experimental studies of masonry on the action of dynamic and static (short-term and long-term) loads are presented. The possibility of plastic deformations in the masonry is analyzed for different types of force effects. The falsity of the proposed approach to the estimation of the coefficient of plasticity of masonry, taking into account the ratio of elastic and total deformations of the masonry is noted. The study of the works of Soviet scientists revealed that the masonry under the action of seismic loads refers to brittle materials in the complete absence of plastic properties in it in the process of instantaneous application of forces. For the cases of uniaxial and plane stress states of the masonry, data on the coefficient of plasticity obtained from the experiment are presented. On the basis of experimental studies the influence of the strength of the so-called base materials (brick, mortar) on the bearing capacity of the masonry, regardless of the nature of the application of forces and the type of its stress state, is noted. The analysis of works of prof. S. V. Polyakov makes it possible to draw a conclusion that at the long application of the load, characteristic for the masonry are not plastic deformations, but creep deformations. It is shown that the proposals of some authors on the need to reduce the level of adhesion of the mortar to the brick for the masonry erected in earthquake-prone regions in order to improve its plastic properties are erroneous both from the structural point of view and from the point of view of ensuring the seismic resistance of structures. It is noted that the proposal to assess the plasticity of the masonry of ceramic brick walls and large-format ceramic stone with a voidness of more than 20% is incorrect, and does not meet the work of the masonry of hollow material. On the basis of the analysis of a large number of research works it is concluded about the fragile work of masonry.

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