Biotechnological Production of Phenyllactic Acid and Biosurfactants from Trimming Vine Shoot Hydrolyzates by Microbial Coculture Fermentation

Coculture fermentations show advantages for producing food additives from agroindustrial wastes, considering that different specified microbial strains are combined to improve the consumption of mixed sugars obtained by hydrolysis. This technology dovetails with both the growing interest of consumers towards the use of natural food additives and with stricter legislations and concern in developed countries towards the management of wastes. The use of this technology allows valorization of both cellulosic and hemicellulosic fractions of trimming vine shoots for the production of lactic acid (LA), phenyllactic acid (PLA), and biosurfactants (BS). This work compares the study of the potential of hemicellulosic and cellulosic fractions of trimming vine shoots as cheaper and renewable carbon sources for PLA and BS production by independent or coculture fermentations. The highest LA and PLA concentrations, 43.0 g/L and 1.58 mM, respectively, were obtained after 144 h during the fermentation of hemicellulosic sugars and simultaneous saccharification and fermentation (SSF) carried out by cocultures of Lactobacillus plantarum and Lactobacillus pentosus. Additionally, cell-bond BS decreased the surface tension (ST) in 17.2 U; meanwhile, cell-free supernatants (CFS) showed antimicrobial activity against Salmonella enterica and Listeria monocytogenes with inhibition halos of 12.1?±?0.6 mm and 11.5?±?0.9 mm, respectively.     

Chiral Determination of Salbutamol,Salmeterol and Atenolol by Two-Dimensional LC–LC: Application to Urine Samples

A heart-cut two-dimensional high-performance liquid chromatography method for enantiomeric determination of salbutamol, salmeterol and atenolol in urine is presented. It involves the use of two separations in a liquid chromatography–liquid chromatography achiral–chiral coupling. Target compounds were previously separated in a primary column (Kinetex™ HILIC, 2.6 μm, 150 × 2.1 mm I.D.) with a mixture of MeOH:ACN:ammonium acetate buffer (5 mM, pH 6) 90:5:5 (v/v/v) as mobile phase at a flow rate of 0.40 mL min⁻¹. Enantiomeric separation was carried out by transferring peak of each compound through a switching valve to a vancomycin chiral column (Chirobiotic™ V, 2.6 μm, 150 × 2.1 mm I.D.) using MeOH:ammonium acetate buffer (2 mM, pH 4) 97:3 (v/v) as mobile phase at a flow rate of 0.50 mL min⁻¹. Ultraviolet detection was done at 227 nm. The method was applied to determine target analytes in urine samples after enzymatic hydrolysis with β-glucuronidase from Helix pomatia, followed by a solid-phase extraction procedure using Isolute^® HCX mixed-mode cartridges. Extraction recoveries ranged from 82 to 90 % in urine samples. Detection limits were 0.091–0.095 μg for each enantiomer of atenolol and between 0.058 and 0.076 and 0.18–0.14 μg for enantiomers of salbutamol and salmeterol, respectively (3 mL of urine). Linearity ranges were between 0.5 and 10 μg mL⁻¹. Intraday and interday reproducibilities of enantiomeric ratio and enantiomeric fraction, expressed as relative standard deviation, were between 1.9 and 9.0 %. The optimized method was successfully applied to the analysis of urine samples obtained from excretion studies in volunteers and in freeze-dried urine samples, containing urinary components with MW < 10,000 and components with MW > 10,000, spiked with different amounts of studied drugs.