scholarly journals Improving biological production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) co-polymer: a critical review

2021 ◽  
Author(s):  
Grazia Policastro ◽  
Antonio Panico ◽  
Massimiliano Fabbricino
Keyword(s):  
Abiotic Factors ◽  
Bacterial Species ◽  
Scale Up ◽  
Carbon Sources ◽  
Operating Conditions ◽  
Production Costs ◽  
Biological Production ◽  
Major Barrier ◽  
Production Methods ◽  
Process Scale Up

AbstractAlthough poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is the most promising biopolymer for petroleum-based plastics replacement, the low processes productivity as well as the high sale price represent a major barrier for its widespread usage. The present work examines comparatively the existing methods to enhance the yield of the PHBV co-polymer biologically produced and/or reduce their costs. The study is addressed to researchers working on the development of new biological production methods and/or the improvement of those currently used. At this aim, the authors have considered the analysis of some crucial aspects related to substrates and microorganism’s choice. The production strategies have been individuated, presented and discussed, either based on a single aspect (type of substrate or microorganism) or based on combined aspects (type of substrate and microorganism). Process operating conditions have been discussed as well. The analysis indicates that the addition of 3HV precursors is capable to dramatically enhance the hydroxyvalerate fraction in the produced biopolymers. On the other hand, due to the high costs of the 3HV precursors, the utilization of wild bacterial species capable to produce the hydroxyvalerate fraction from unrelated carbon sources (i.e. no 3HV precursors) also can be considered a valuable strategy for costs reduction. Moreover, metabolic engineering techniques can be successfully used to promote 3HV precursors-independent biosynthesis pathways and enhance the process productivity. The use of mixed cultures or extremophile bacteria avoids the need of sterile working conditions, and therefore favours the process scale-up. The utilization of the organic waste as substrate plays a key role for a sharp reduction of production costs. Finally, the selection of the most suitable substrate-microorganism combination cannot be separated by the adoption of an appropriate choice of reactor configuration and abiotic factors. Graphic abstract

Microfiltration of vinasse: sustainable strategy to improve its nutritive potential

2015 ◽  
Vol 73 (6) ◽  
pp. 1434-1441 ◽  
Author(s):  
Míriam C. S. Amaral ◽  
Laura H. Andrade ◽  
Luzia S. F. Neta ◽  
Natalie C. Magalhães ◽  
Fábio S. Santos ◽  
...  
Keyword(s):  
Recovery Rate ◽  
Scale Up ◽  
Operating Conditions ◽  
Soil Bioremediation ◽  
Permeate Flux ◽  
Bench Scale ◽  
Process Scale Up ◽  
Nutrients Concentration ◽  
Process Scale ◽  
Rate Profile

The purpose of this article was to evaluate and establish microfiltration (MF) operating conditions for vinasse (ethanol industries wastewater also known as stillage, slop, distillery effluent or dunder) concentration aiming to improve the use of its nutritive potential. The operating conditions influence permeate flux that has been evaluated by monitoring the flow rate profile during the operation on bench scale in different conditions (feed pH, aeration condition and recovery rate). From the results found, the process scale up was then effected. The bench scale findings showed that the vinasse microfiltration under air flow of 0.5 m3.h−1 between membrane fibers, with no pH adjustment, and recovery rate of 93% produced two flows, one of permeate that may be used to wash the sugarcane during the ethanol production processing, and the other of concentrate that contains a high organic compounds and nutrients concentration. This concentrate has additional potentiality of being used as organic compound supplement in contaminated soil bioremediation, and as a supplier of microbial biomass or substrate for biosurfactant production.

scholarly journals Denitrification Control in a Recirculating Aquaculture System—A Simulation Study

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1306
Author(s):  
Pedro Almeida ◽  
Laurent Dewasme ◽  
Alain Vande Wouwer
Keyword(s):  
Carbon Source ◽  
Carbon Sources ◽  
Aquatic Organisms ◽  
Operating Conditions ◽  
Toxic Substances ◽  
Recirculating Aquaculture System ◽  
Treatment Technology ◽  
Tuning Method ◽  
Recirculating Aquaculture ◽  
Aquaculture System

The recirculating aquaculture system (RAS) is a land-based water treatment technology, which allows for farming aquatic organisms, such as fish, by reusing the water in the production (often less than 5%). This technology is based on the use of filters, either mechanical or biological, and can, in principle, be used for any species grown in aquaculture. Due to the low recirculation rate, ammonia accumulates in the system and must be converted into nitrate using nitrification reactors. Although less toxic for fish, nitrate can also be further reduced into nitrogen gas by the use of denitrification biofilters which may create several issues, such as incomplete denitrification, resulting in toxic substances, such as nitrite and nitric oxide, or a waste of carbon source in excess. Control of the added quantity of carbon source in the denitrification biofilter is then mandatory to keep nitrate/nitrite concentrations under toxic levels for fish and in accordance with local effluent regulations, and to reduce costs related to wasted organic carbon sources. This study therefore investigates the application of different control methodologies to a denitrification reactor in a RAS. To this end, a numerical simulator is built to predict the RAS behavior and to allow for the comparison of different control approaches, in the presence of changes in the operating conditions, such as fish density and biofilter removal efficiency. First, a classical proportional-integral-derivative (PID) controller was designed, based on an SIMC tuning method depending on the amount of ammonia excreted by fish. Then, linearizing and cascade controllers were considered as possible alternatives.

scholarly journals Complete biosynthesis of a sulfated chondroitin in Escherichia coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Adeola Awofiranye ◽  
Payel Datta ◽  
Ke Xia ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Scale Up ◽  
Production Methods ◽  
E Coli ◽  
Microbial Cell Factories ◽  
Cell Factories ◽  
Microbial Product ◽  
Dry Cell Weight ◽  
One Step ◽  
Dry Cell

AbstractSulfated glycosaminoglycans (GAGs) are a class of important biologics that are currently manufactured by extraction from animal tissues. Although such methods are unsustainable and prone to contamination, animal-free production methods have not emerged as competitive alternatives due to complexities in scale-up, requirement for multiple stages and cost of co-factors and purification. Here, we demonstrate the development of single microbial cell factories capable of complete, one-step biosynthesis of chondroitin sulfate (CS), a type of GAG. We engineer E. coli to produce all three required components for CS production–chondroitin, sulfate donor and sulfotransferase. In this way, we achieve intracellular CS production of ~27 μg/g dry-cell-weight with about 96% of the disaccharides sulfated. We further explore four different factors that can affect the sulfation levels of this microbial product. Overall, this is a demonstration of simple, one-step microbial production of a sulfated GAG and marks an important step in the animal-free production of these molecules.

scholarly journals Farmer Field Schools (FFSs): A Tool Empowering Sustainability and Food Security in Peasant Farming Systems in the Nicaraguan Highlands

2018 ◽  
Vol 10 (9) ◽  
pp. 3020 ◽  
Author(s):  
Esperanza Arnés ◽  
Carlos G. H. Díaz-Ambrona ◽  
Omar Marín-González ◽  
Marta Astier
Keyword(s):  
Food Security ◽  
Scale Up ◽  
Farming Systems ◽  
Farming System ◽  
Production Costs ◽  
Farmer Field Schools ◽  
Basic Services ◽  
Long Term Impact ◽  
Field Schools ◽  
The Impact

Farmer field schools (FFSs) emerged in response to the gap left by the worldwide decline in agricultural extension services. With time, this methodology has been adapted to specific rural contexts to solve problems related to the sustainability of peasant-farming systems. In this study we draw upon empirical data regarding the peasant-farming system in the Nicaraguan highlands to evaluate whether FFSs have helped communities improve the sustainability of their systems and the food security of their residents using socioeconomic, environmental, and food and nutrition security (FNS) indicators. In order to appreciate the long-term impact, we studied three communities where FFSs were implemented eight, five, and three years ago, respectively, and we included participants and nonparticipants from each community. We found that FFSs have a gradual impact, as there are significant differences between participants and nonparticipants, and it is the community that first implemented FFSs that scores highest. The impact of FFSs is broad and long lasting for indicators related to participation, access to basic services, and conservation of natural resources. Finally, this paper provides evidence that FFSs have the potential to empower farmers; however, more attention needs to be paid to critical indicators like production costs and the use of external inputs in order to scale up their potential in the future.

scholarly journals Impact of Different Carbon Sources on the in vitro Growth and Viability of Escherichia coli (SUBE01) and Salmonella spp. (SUBS01) Cells

2016 ◽  
pp. 39-44
Author(s):  
Ifra Tun Nur ◽  
Jannatun Tahera ◽  
Md Sakil Munna ◽  
M Majibur Rahman ◽  
Rashed Noor
Keyword(s):  
Escherichia Coli ◽  
Bacterial Growth ◽  
Culture Media ◽  
Bacterial Species ◽  
Carbon Sources ◽  
Growth Dynamics ◽  
Luria Bertani ◽  
Tween 20 ◽  
Salmonella Spp

With a previous observation of Escherichia coli growth cessation along with temperature variation within three different bacteriological culture media (nutrient agar, Luria-Bertani agar and minimal agar), current investigation further depicted on the possible growth dynamics of Escherichia coli (SUBE01) and Salmonella (SUBS01) growth and viability upon supplementation of different carbon sources (dextrose, sucrose, lactose, glycerol and tween 20) at 37°C under the aeration of 100 rpm. Viability of the tested bacterial species was assessed through the enumeration of the colony forming unit (cfu) appeared upon prescribed incubation for 12-24 hours on different agar plates consisting of the above mentioned carbon sources. Besides, to inspect the cellular phenotypic changes, morphological observations were conducted under the light microscope. Variations in bacterial growth (either growth acceleration or cessation) were further noticed through the spot tests on the agar plates. Considerable shortfalls in the culturable cells of E. coli and Salmonella spp. were noted in the minimal media separately consisting of sucrose, lactose, glycerol or tween 20 while an opposite impact of accelerated growth was noticed in the media supplied with dextrose. The data revealed a hierarchy of consequence of carbon sources as nutrient generators whereby the favourable bacterial growth and survival order of the carbon sources was estimated as dextrose > glycerol > lactose > tween 20 > sucrose.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 39-44

scholarly journals Assessing the Microbial Communities in Four Different Daqusby Using PCR-DGGE, PLFA, and Biolog Analyses

2020 ◽  
Vol 69 (1) ◽  
pp. 27-37
Author(s):  
YUXI LING ◽  
WENYING LI ◽  
TONG TONG ◽  
ZUMING LI ◽  
QIAN LI ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Phospholipid Fatty Acid ◽  
Bacterial Species ◽  
Carbon Sources ◽  
Bacterial Biomass ◽  
Biolog Ecoplates ◽  
Different Types ◽  
Gradient Gel Electrophoresis ◽  
Plfa Analysis

Daqu made from raw wheat, barley or pea is used as an inoculum for the fermentation of Chinese Baijiu. In this study, the microbial communities of four different types of Daqus (sauce-flavor Wuling Daqu, sauce and strong-flavor Baisha Daqu, strong-flavor Deshan Daqu, and light-flavor Niulanshan Daqu) were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), phospholipid fatty acid (PLFA) analysis, and Biolog EcoPlates analysis (Biolog). Clear differences were seen between the microbial communities of the four Daqus. PCR-DGGE showed differences in the number and brightness of bands between the Daqus, indicating the presence of unique bacterial species in Deshan Daqu, Wuling Daqu, and Niulanshan Daqu. Lactobacillus sanfranciscensis, Bacillus thermoamylovorans, and some unclassified bacteria were unique to Wuling Daqu, Deshan Daqu, and Niulanshan Daqu, respectively. Moreover, some bacterial species were observed in all four Daqus. A total of 26 PLFAs between C12 to C20 were detected from the four Daqus by PLFA analysis. Wuling Daqu had the highest total and fungal biomasses, Baisha Daqu had the highest bacterial biomass, and Niulanshan Daqu had the highest ratio of fungal biomass to bacterial biomass. The Biolog results indicated differences in the carbon source use and mode of the four Daqus, and also demonstrated that each Daqu had varying abilities to utilize different types of carbon sources. The cluster analysis of the three methods showed that the microbial communities of the four Daqus were different. This study also demonstrates the applicability of the three analytical methods in the evaluating of the microbial communities of Daqus.

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