Corrigendum to “Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel”

The large increase in the world population has resulted in a very large amount of construction waste, as well as a large amount of waste glycerol from transesterification reactions of acyl glycerides from oils and fats, in particular from the production of biodiesel. Only a limited percentage of these two residues are recycled, which generates a large management problem worldwide. For that reason, in this study, we used crude glycerol as a carbon source to cultivate polyhydroxyalkanoates (PHA)-producing mixed microbial cultures (MMC). Two bioproducts derived from these cultures were applied on the surface of concrete with recycled aggregate to create a protective layer. To evaluate the effect of the treatments, tests of water absorption by capillarity and under low pressure with Karsten tubes were performed. Furthermore, SEM-EDS analysis showed the physical barrier caused by biotreatments that produced a reduction on capillarity water absorption of up to 20% and improved the impermeability of recycled concrete against the penetration of water under pressure up to 2.7 times relative to the reference. Therefore, this bioproduct shown to be a promising treatment to protect against penetration of water to concrete surfaces increasing its durability and useful life.

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Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel

BioMed Research International ◽

10.1155/2015/932934 ◽

2015 ◽

Vol 2015 ◽

pp. 1-14 ◽

Cited By ~ 18

Author(s):

C. Varrone ◽

T. M. B. Heggeset ◽

S. B. Le ◽

T. Haugen ◽

S. Markussen ◽

...

Keyword(s):

Crude Glycerol ◽

Degradation Efficiency ◽

Anaerobic Sludge ◽

Growth Media ◽

Fed Batch ◽

Microbial Composition ◽

Fermentation Products ◽

Substrate Degradation ◽

Microbial Cultures ◽

Mixed Microbial Cultures

Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs), able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable and stable MMC, trying to overcome inhibition problems and enhance substrate degradation efficiency, as well as generation of soluble fermentation products. Repeated transfers in small batches and fed-batch conditions have been applied, comparing the use of different inoculum, growth media, and Kinetic Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h) and different dominant metabolic products were obtained, depending on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate). On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1,3-propanediol and butyrate production. Changes in microbial composition were monitored by means of Next Generation Sequencing, revealing a dominance of glycerol consuming species, such asClostridium,Klebsiella, andEscherichia.

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Polyhydroxyalkanoates production by aerobic mixed microbial cultures using crude glycerol

New Biotechnology ◽

10.1016/j.nbt.2014.05.1688 ◽

2014 ◽

Vol 31 ◽

pp. S33

Author(s):

Paulo Costa Lemos ◽

Rita Moita ◽

André Freches ◽

Rita Pontes

Keyword(s):

Crude Glycerol ◽

Microbial Cultures ◽

Mixed Microbial Cultures

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Crude glycerol as feedstock for polyhydroxyalkanoates production by mixed microbial cultures

Water Research ◽

10.1016/j.watres.2014.03.066 ◽

2014 ◽

Vol 58 ◽

pp. 9-20 ◽

Cited By ~ 55

Author(s):

R. Moita ◽

A. Freches ◽

P.C. Lemos

Keyword(s):

Crude Glycerol ◽

Microbial Cultures ◽

Mixed Microbial Cultures

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Beyond PHA: Stimulating intracellular accumulation of added-value compounds in mixed microbial cultures

Bioresource Technology ◽

10.1016/j.biortech.2021.125381 ◽

2021 ◽

pp. 125381

Author(s):

F. Pinto-Ibieta ◽

A. Serrano ◽

M. Cea ◽

G. Ciudad ◽

F.G. Fermoso

Keyword(s):

Added Value ◽

Intracellular Accumulation ◽

Microbial Cultures ◽

Mixed Microbial Cultures

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

Water ◽

10.3390/w13070897 ◽

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.

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