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In this work, the performance of
dehydratation-desalcoholization system based on an electronic nose coupled to
gas chromatography was tested. The system was used for monitoring the volatile
compounds produced during a lactic fermentation with a heterofermentative
bacteria (Lactobacillus fermentum Ogi E1). The monitoring was carried out
with dehydratation and desalcoholization or dehydratation only, on the basis of
low ethanol concentration produced by this bacteria. In the first case,
fermentation head-space analyses showed low signals from each gas sensor, then
the principal components analyses (PCA) resulted confused. However with the
only dehydratation system, the electronic nose was able to detect some volatile
compounds during bioprocess. The PCA showed a single distribution, permitting
to conclude that principal component 1 represented the ethanol concentration.
The system is appropriate to monitor some parameters during the fermentations
process as ethanol, lactate and biomass concentration.
objectives of the present study were to recover and identify volatiles organic
compounds (VOCs) in the wastewater (WW) coming from a soluble coffee industrial
plant. For VOCs recover, the WW was concentrated by pervaporation using a
polydimethylsiloxane (PDMS) membrane. Furthermore, the solid phase micro
extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) were used
for VOCs identification. The multivariate method of principal component
analysis (PCA) was performed to evaluate differences amongst the feed and
concentrate streams. Regarding the number of VOCs identified in the wastewater (33) and permeate (72), a significant
statistical difference at p < 0.05 was observed. Clusters discriminating were
clearly observed, as the feed and permeate streams are compared. Thus, we
can conclude that pervaporation process using a PDMS membrane was effective to
recover different class of VOCs present in the aqueous effluent and can be
recommended for industrial wastewater treatment.
The apparent solubility controls the initial stage of
supercritical fluid extraction of natural products, which is most important
for the process economics. Based on the literature, data on CO2 apparent solubility of volatile substances from different matrices as leaves,
flowers, rhizomes and seeds were collected and compared with their
thermodynamic solubility. The adsorption isotherm derived by del Valle and Urrego as a
modification of the isotherm proposed by Perrut et al. is universal enough to interpret these data as well as the
apparent solubility of vegetable oils from seeds, for which it was originally
proposed. When the apparent solubility of minor extract components in CO2 is compared with their thermodynamic solubility, their fraction in the
extracted mixture should be taken into account.
BTX (benzene, ethylbenzene, toluene and p-xylene)
and meteorological parameters were measured in ambient air of an urban site
located in Carmen City, Campeche, Mexico. A total of 412 samples were collected
for BTX and analyzed by Gas Chromatography with Flame Ionization Detection (GC-FID).
Meteorological parameters were measured by a portable station. A marked diurnal
variation was found for all measured BTX. The highest concentrations occurred
during midday (13:00-14:30 h). A clear seasonal pattern was observed too for
all compounds registering their highest levels during summer sampling period.
Mean concentrations for benzene, ethylbenzene, toluene and p-xylene were: 5.42,
3.97, 11.24 and 8.32 ppbv, respectively. BTX abundance showed the following
order: toluene > p-xylene > benzene >
ethylbenzene. BTX maximum concentrations were found when winds blowed from E
and NE. Important oil industry sources and avenues are located at these
directions. These sources could contribute to the levels of BTX in this site.
Bacanora is an artisanal beverage distilled from agave,
which is manufactured on a small scale in the Sonora state, México. The aim of
this study was to identify the major volatile compounds in 77 artisanal Bacanora
beverages by gas chromatography, to determine the samples that comply with the
Mexican Standards for Bacanora. The samples were collected in 28 municipalities
in the area of origin denomination. It was found that only 55.8% of the samples
(43) meet the parameters established in the Official Mexican Standards, whereas
44.2% of the samples (34) do not comply: 3 samples for alcohol content, 8 for
acetaldehyde, 1 for esters, 11 for methanol and 17 for higher alcohols. Some of
the samples do not comply because of more than one analyzed parameter. The Bacanora
samples showed great variability among the sampled regions as well as within
the same municipalities (p ≤ 0.05).
Volatile organic compounds (VOCs) are harmful to human health and the environment. Recently, loess (Hwangtoh) was used as an eco-friendly interior paint formulation in Korea. It is used even more commonly as a filter carrier to remove VOCs. In this study, we isolated Bacillus strains from a loess filter. The strains that were tolerant to VOCs were labeled according to the series VOC01 to VOC35. Four strains—VOC03, VOC11, VOC18, and VOC30—were investigated for their ability to degrade cyclohexane and toluene. Strain VOC18 best degraded both VOCs, whereas VOC03 demonstrated no ability to degrade VOCs. In keeping with this, VOC18 grew best on cyclohexane or toluene as the sole carbon source. The strains were identified by their physiochemical and phylogenetic characteristics. Strain VOC18 was determined as a strain of Bacillus cereus; VOC11 and VOC30 were determined as differentiated strains of B. thuringiensis. Strain VOC03, which demonstrated high tolerance but no ability to degrade VOCs, was identified as a strain of B. megaterium.