Evaluation of biotreatability of ionic liquids in aerobic and anaerobic conditions

2014 ◽  
Vol 70 (4) ◽  
pp. 698-704 ◽  
Author(s):  
Andreja Žgajnar Gotvajn ◽  
Elizabeta Tratar-Pirc ◽  
Peter Bukovec ◽  
Polona Žnidaršič Plazl

The aim of our study was to set up an approach for reliable biotreatability assessment of ionic liquids (ILs). As a case study, two different ILs were selected: pyridinium-based 1-butyl-3-methylpyridinium dicyanamide ([bmpyr][dca]) and imidazolium-based 1-butyl-3-methylimidazole tetrafluoroborate ([bmim][BF4]). Toxicity in aerobic conditions was determined by measurement of inhibition of oxygen consumption by activated sludge, while their biodegradability was calculated from measurements of oxygen consumption and dissolved organic carbon elimination. For their biotreatability in anaerobic conditions, the method with measurement of biogas production has been employed comparing flocculent and granular sludge. Both ILs were less toxic and more biodegradable in anaerobic conditions. IL [bmpyr][dca] was not toxic to granular sludge up to 742 mg L−1 and it even has been degraded at this concentration in the presence of easily degradable glucose. Flocculent sludge was completely inhibited at the lower concentration of 318 mg L−1, but it degraded by 44% at 106 mg L−1 in the presence of glucose, indicating the appearance of cometabolism. IL [bmim][BF4] was less toxic but also resistant to biodegradation in anaerobic conditions. It degraded via cometabolism 21% at 1,452 mg L−1. It has been concluded that any assessment of biotreatability of ILs should include parallel determination in aerobic and anaerobic conditions.

2020 ◽  
Vol 85 (4) ◽  
pp. 1005-1015
Author(s):  
Kentaro Ochi ◽  
Maho Tokuda ◽  
Kosuke Yanagiya ◽  
Chiho Suzuki-Minakuchi ◽  
Hideaki Nojiri ◽  
...  

ABSTRACT The frequency of transconjugants were compared for the incompatibility (Inc) P-1 and P-7 plasmids pBP136 and pCAR1 under aerobic and anaerobic conditions. Filter mating assays were performed with one donor strain and one recipient strain using different donors of Pseudomonas and recipient strains, including Pseudomonas, Pantoea, and Buttiauxella. Under anaerobic condition, frequencies of transconjugants for both plasmids were 101-103-fold lower than those under aerobic condition regardless of whether aerobically or anaerobically grown donors and recipients were used. To compare the transconjugant ranges under aerobic and anaerobic conditions, conjugation was performed between the donor of pBP136 and recipient bacteria extracted from environmental samples. Several transconjugants were uniquely obtained from each aerobic or anaerobic condition. Our findings indicate that a plasmid can differently spread among bacteria depending on the oxygen concentrations of the environment.


1946 ◽  
Vol 24f (1) ◽  
pp. 1-11 ◽  
Author(s):  
G. A. Adams

Aeration by mechanical agitation of 15% wheat mash fermented by Aerobacillus polymyxa inhibited the formation of 2,3-butanediol and particularly of ethanol. Aeration of similar mashes by passage of finely dispersed air or oxygen at the rate of 333 ml. per minute per litre of mash increased the rate of formation and yield of 2,3-butanediol but inhibited ethanol formation. However, the over-all time required for the completion of fermentation was not shortened from the usual 72 to 96 hr. required for unaerated mashes. There was no evidence of a shift from fermentative to oxidative dissimilation. Under aerobic conditions, the final butanediol–ethanol ratio was approximately 3:1. Anaerobic conditions, as produced by the passage of nitrogen or hydrogen through the mash, increased the rate of formation of both butanediol and ethanol and shortened the fermentation time to about 48 hr. Under these conditions, the butanediol–ethanol ratio was reduced to about 1.3:1.0. Carbon dioxide gave a butanediol–ethanol ratio resembling that of anaerobic fermentation but did not reduce fermentation time.


Author(s):  
Irina Alina Chera Anghel ◽  
Loredana Popescu

The most commonly used insulating liquid in transformers is mineral oil. Special synthetic applications such as silicone, ester, perchloroethene, etc. are used today in special applications, with different characteristics, very low or nonexistent toxicity to mineral oils used in transformers. On the other hand, they have a much better biodegradability than mineral oils in both aerobic and anaerobic conditions. But they cannot directly replace the mineral oil in operation or in repaired units. They have dielectric properties and good heat transfer but have limited their use to special transformers due to the relatively high cost and availability.


Sign in / Sign up

Export Citation Format

Share Document