Biodiesel-Derived Glycerol Obtained from Renewable Biomass—A Suitable Substrate for the Growth of Candida zeylanoides Yeast Strain ATCC 20367

Abstract

Used kitchen oil represents a feasible and renewable biomass to produce green biofuels such as biodiesel. Biodiesel production generates large amounts of by-products such as the crude glycerol fraction, which can be further used biotechnologically as a valuable nutrient for many microorganisms. In this study, we transesterified used kitchen oil with methanol and sodium hydroxide in order to obtain biodiesel and crude glycerol fractions. The crude glycerol fraction consisting of 30% glycerol was integrated into a bioreactor cultivation process as a nutrient source for the growth of Candida zeylanoides ATCC 20367. Cell viability and biomass production were similar to those obtained with batch cultivations on pure glycerol or glucose as the main nutrient substrates. However, the biosynthesis of organic acids (e.g., citric and succinic) was significantly different compared to pure glycerol and glucose used as main carbon sources.

Active Packaging—Poly(Vinyl Alcohol) Films Enriched with Tomato By-Products Extract

“…Peaks of different heights situated between and 3000 cm −1 were observed for all tested films (2906 and 2939 cm −1 for PVA, 2908 and 2939 cm −1 for PVA + TBE, 2910 and 3022 for PVA + Ia, 2854 and 2922 for PVA + Ia + TBE, and 2854 and 2924 cm −1 for PVA+Ch and PVA + Ch + TBE). Their presence was connected with vibrations of C-H bonding specific to polyalcohols, as the scientific literature suggests [74][75][76]. Moderate peaks associated with -C-C-C-vibrations were identified around 1400 cm −1 (at 1417 cm −1 for PVA, PVA + TBE, and PVA + Ia + TBE; and at 1411 cm −1 for PVA + Ch + TBE) [75].…”

“…The physical measurements of the solid PVA-based films; the shown data represent the mean value of three replicates with the standard deviation (±). FTIR is a useful method to identify specific molecular structures or the vibration of functional groups from certain matrices [73,74]. For the present study, FTIR analysis was performed for PVA-based films supplemented with TBE ( Figure 6) in order to observe the influence of tomato waste-based extract on the PVA formulations.…”

Poly(vinyl alcohol)-Based Biofilms Plasticized with Polyols and Colored with Pigments Extracted from Tomato By-Products

“…Fourier-transform infrared spectroscopy is a very utilized method for the detection of chemical constitutions and possible interactions between polymer compositions [71,72]. The FTIR results obtained for the present work are illustrated in Figure 7.…”

Klebsiella pneumoniae—A Useful Pathogenic Strain for Biotechnological Purposes: Diols Biosynthesis under Controlled and Uncontrolled pH Levels

“…Glycerol consumption, PDO, and BDO production were measured by HPLC after the derivatization process [55,56]. The HPLC unit (Agilent 1200, Santa Clara, CA, USA) was equipped with quaternary pump, solvent degasser, auto-sampler, UV-Vis photodiode detector (DAD) coupled with single quadrupole mass detector (MS, Agilent 6110), equipped with electrospray ionization source (ESI) (Agilent Technologies, Santa Clara, CA, USA), and controlled by Agilent ChemStation software.…”

“…The viability of the Klebsiella cells was determined by plate counting method proposed by Ziegler and Halvorson [24,56,57]. Microscopic analysis consisting of methylene blue staining was applied in order to observe the bacterial cell morphology and appearance.…”