Aerobic and Anaerobic Reduction of Cr(VI) byShewanella oneidensis Effects of Cationic Metals, Sorbing Agents and Mixed Microbial Cultures (Acta Biotechnologica 23 (2003)2–3,161 178)

2003 ◽  
Vol 23 (4) ◽  
pp. 396-396
Author(s):  
K. L. Lowe ◽  
W. Straube ◽  
B. Little ◽  
J. Jones-Meehan
Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 897
Author(s):  
Neda Amanat ◽  
Bruna Matturro ◽  
Marta Maria Rossi ◽  
Francesco Valentino ◽  
Marianna Villano ◽  
...  

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.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2057
Author(s):  
Lorena Serrano-González ◽  
Daniel Merino-Maldonado ◽  
Manuel Ignacio Guerra-Romero ◽  
Julia María Morán-del Pozo ◽  
Paulo Costa Lemos ◽  
...  

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.


2001 ◽  
Vol 67 (3) ◽  
pp. 1076-1084 ◽  
Author(s):  
Jeff McLean ◽  
Terry J. Beveridge

ABSTRACT A pseudomonad (CRB5) isolated from a decommissioned wood preservation site reduced toxic chromate [Cr(VI)] to an insoluble Cr(III) precipitate under aerobic and anaerobic conditions. CRB5 tolerated up to 520 mg of Cr(VI) liter−1 and reduced chromate in the presence of copper and arsenate. Under anaerobic conditions it also reduced Co(III) and U(VI), partially internalizing each metal. Metal precipitates were also found on the surface of the outer membrane and (sometimes) on a capsule. The results showed that chromate reduction by CRB5 was mediated by a soluble enzyme that was largely contained in the cytoplasm but also found outside of the cells. The crude reductase activity in the soluble fraction showed aKm of 23 mg liter−1 (437 μM) and a V max of 0.98 mg of Cr h−1 mg of protein−1 (317 nmol min−1 mg of protein−1). Minor membrane-associated Cr(VI) reduction under anaerobiosis may account for anaerobic reduction of chromate under nongrowth conditions with an organic electron donor present. Chromate reduction under both aerobic and anaerobic conditions may be a detoxification strategy for the bacterium which could be exploited to bioremediate chromate-contaminated or other toxic heavy metal-contaminated environments.


2011 ◽  
Vol 102 (10) ◽  
pp. 5589-5595 ◽  
Author(s):  
T. Olmez-Hanci ◽  
I. Arslan-Alaton ◽  
D. Orhon ◽  
O. Karahan ◽  
E. Ubay Cokgor ◽  
...  

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Huiqin Zhang ◽  
Yan Li ◽  
Xin Wang ◽  
Anhuai Lu ◽  
Hongrui Ding ◽  
...  

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