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The superficial gas velocity (Ug) values of 1.0, 1.5 and 2.0 cm s−1 showed a diesel consumption of 59.70, 58.20 and 65.20 %, respectively. The productivity of the airlift bioreactors (ALBs) was 0.030, 0.026 and 0.034 g L−1 d−1, respectively. During 10 days of operation, the emulsification index (E24 %) values for Ug 1.0, 2.0 and 2.0 cm s−1 were 15.79, 15.07 and 12.85 %, respectively. Likewise, an increase in the degradation and suspended solids was observed when increasing the Ug from 1.0 to 2.0 cm s−1 of the ALBs, whereas a decrease in emulsification index E24 % was observed for an Ug of 2.0 cm s−1. According to the results, the Ug of 2.0 cm s−1 was the most effective for increasing the degradation of diesel and growth of the consortium among the Ug evaluated. Furthermore, the reduction of E24 % in this Ug suggests that the consortium uses a mixed form of hydrocarbon consumption, both by direct contact and in emulsified form. [ABSTRACT FROM AUTHOR]

Chromium Cr(VI) is a highly toxic environmental contaminant for any organism, its presence in the environment is mainly due to anthropogenic activities. The use of biotechnology has been implemented for the treatment of effluents contaminated with Cr(VI).Our working group has isolated several fungi and bacteria capable of removing Cr(VI) from the culture medium. Aspergillus niger var tubingensis Ed8 is a strain that can produce metabolites which reduce Cr (VI) to Cr (III). The objective of this work was to determine the effect of sodium salicylate on the growth of this strain and on the Cr(VI) reduction system, as well as to identify the metabolites that are produced from sodium salicylate. Our results show that the Culture medium containing sodium salicylate (20 mM) inhibits strain growth compared to the control condition (0 mM). However, it increases the specific reduction capacity of Cr (VI) red/mg Biomass in order of magnitude. Analysis of the culture medium corresponding to 48 h of incubation shows the presence of catechol and salicylate diminution. In addition, as a product of the enzymatic activity of a cell-free cellular extract, after 24 h of incubation, the consumption of salicylate is detected, as well as the presence of peaks corresponding to resorcinol and catechol. Our results show that it is possible to increase the Cr(VI) reducing capacity of the Ed8 strain, depending on the composition of the culture medium. [ABSTRACT FROM AUTHOR]

Notwithstanding the benefits that oil provides as a source of energy, society also recognizes the environmental problems caused by its use. We evaluated eight coastal sites in the central area of the Gulf of Mexico. At these sites, 14 hydrocarbons were detected which belong to compounds formed by carbons ranging from C9 to C27. The hydrocarbons with the highest concentrations were n-nonane (3.07 ± 1.60 mg L−1), carbazole (0.93 ± 0.12 mg L−1) and benzo [a] pyrene (1.33 ± 0.71 mg L−1). The hydrocarbons found belong mostly to medium fraction hydrocarbons, which are mostly found in fuels such as diesel. Therefore, this fuel was used as a carbon source or substrate in bubble column bioreactors. The capacity of non-genetically modified organisms to degrade microbial hydrocarbons was evaluated using a mineral medium for a period of 14 days. Suspended solids increased from 0.8 to 2.94 g L−1. Diesel consumption was achieved in 12 days of operation. [ABSTRACT FROM AUTHOR]

The hydrodynamic behavior of bubble column bioreactors (BCB) is strongly dependent on the bubbly flow regime. Therefore, the influence of superficial gas velocity (Ug) and Sauter mean diameter (d32) on gas hold up (εg) was evaluated for the cultivation of a petroleum-degrading consortium. Hydrodynamic parameters were determined by photographic techniques. Also, the biomass cultivation was quantified by suspended solids formation (SS). Our findings indicated that the d32 increased at high Ug values (0.9-1.2 cm s-1), but decreased with the presence of Tween 20 surfactant (0-0.15 mL L-1) in the model medium. An enhancement in the εg was observed at high Ug values (1.0-1.3 cm s-1). Interestingly, εg values ranging from 0.02 to 0.024 reported a high concentration level of SS (8-10 g L-1) during the hexadecane degradation. Particularly, εg value of 0.024 was a convenient level to cultivate the consortium resulting in changes in bacterial population distribution, due to oxygen and hydrocarbon bioavailability. According our results, the εg is proposed as key factor related to mass transfer phenomena and agitation on the cultivation of petroleum-degrading consortium. [ABSTRACT FROM AUTHOR]

Practical Application The effect of solvents with different polarities on the recovery of phytochemicals (carotenoids, capsaicinoids, and phenolic compounds) from habanero pepper (Capsicum chinense) and their association with antioxidant activity (ABTS•+ and DPPH) was evaluated through Ultra‐Performance‐Liquid Chromatography coupled with a Photodiode Array Detector and a Electrospray Ionization Mass Spectrometry (UPLC‐PDA‐ESI‐MS)‐based chemometric analysis, including linear correlation, multiple linear regression, and principal component analysis (PCA). The solvent polarity scale was established according to solvent dielectric constants (ɛ). Color variation (ΔE) was used to determine the presence of carotenoids, with the highest ΔE obtained using low‐polarity solvents (hexane and ethyl acetate). A high content of capsaicin and dihydrocapsaicin was recovered with acetone (4.29 and 3.76 mg g⁻¹ dry weight, respectively). Phenolic compounds such as N‐caffeoyl putrescine and derivatives of luteolin and apigenin were identified through mass spectrometry. A high recovery (26.54–31.74 mg GAE g⁻¹ dry weight) of these compounds was obtained using intermediate‐polarity solvents. The PCA revealed clustering of solvents based on their affinity for extracting specific compounds and their association with antioxidant activity. A significant correlation was observed between ΔE and DPPH, indicating that carotenoid pigments exhibited higher DPPH radical inhibition capacity than other compounds. Total phenolic content (TPC) and phenolic compounds (phenolpolyamides, hydroxycinnamic acids, and hydroxybenzoic acids) were clustered with the ABTS•+ radical inhibition assay. The information obtained is crucial for selecting suitable solvents in the extraction and purification protocols of bioactive compounds. It is also valuable for conducting plant metabolomic analyses and for studies focused on determining the effects of bioactive compounds in food, pharmaceutical, and cosmeceutical applications.The results describe the characteristics of the extracts obtained using different solvents. Therefore, the information may be useful for establishing extraction protocols for phytochemical compounds in fruits from Capsicum chinense for various purposes, such as metabolomic analysis, the recovery of specific compounds with antioxidant activity, and food applications. [ABSTRACT FROM AUTHOR]