Recycling of waste glycerol derived from biodiesel production to high value-added chemicals is essential for sustainable development of Bio-Circular-Green Economy. This work studied the conversion of glycerol to 1,3-propanediol over Pt/WOₓ/Al₂O₃ catalysts, pointing out the impacts of catalyst pore sizes and operating conditions for maximizing the yield of 1,3-propanediol. The results suggested that both pore confinement effect and number of available reactive metals as well as operating conditions determined the glycerol conversion and 1,3-propanediol selectivity. The small-pore 5Pt/WOₓ/S–Al₂O₃ catalyst (6.1 nm) gave a higher Pt dispersion (32.0%), a smaller Pt crystallite size (3.5 nm) and a higher number of acidity (0.47 mmol NH₃ g⁻¹) compared to those of the large-pore 5Pt/WOₓ/L-Al₂O₃ catalyst (40.3 nm). However, glycerol conversion and 1,3-propanediol yield over the small-pore 5Pt/WOₓ/S–Al₂O₃ catalyst were significantly lower than those of the large-pore Pt/WOₓ/L-Al₂O₃ catalyst, suggesting that the diffusional restriction within the small-pore catalyst suppressed transportation of molecules to expose catalytic active sites, favoring the excessive hydrogenolysis of 1,3-propanediol, giving rise to undesirable products. The best 1,3-propanediol yield of 32.8% at 78% glycerol conversion were achieved over the 5Pt/WOₓ/L-Al₂O₃ under optimal reaction condition of 220 °C, 6 MPa, 5 h reaction time and amount of catalyst to glycerol ratio of 0.25 g mL⁻¹. However, the 1,3-propanediol yield and glycerol conversion decreased to 19.6% and 51% after the 4th reaction-regeneration which were attributed to the carbonaceous deposition and the agglomeration of Pt particles.

Methane (CH₄) production from anaerobic digestion of solid and liquid agro-industrial wastes is an attractive strategy to meet the growing need for renewable energy sources and promote environmentally appropriate disposal of organic wastes. This work aimed at determining the CH₄ production potential of six agro-industrial wastewaters (AWW), evaluating the most promising for methanization purposes. It also aims to provide kinetic parameters and stoichiometric coefficients of CH₄ production and define which kinetic models are most suitable for simulating the CH₄ production of the evaluated substrates. The AWW studied were swine wastewater (SW), slaughterhouse wastewater (SHW), dairy wastewater (DW), brewery wastewater (BW), fruit processing wastewater (FPW), and residual glycerol (RG) of biodiesel production. RG was the substrate that showed the highest methanization potential. Exponential kinetic models can be efficiently applied for describing CH₄ production of more soluble substrates. On the other hand, logistic models were more suitable to predict the CH₄ production of more complex substrates.

In current study, we investigated the changes of proteome profiles of Pycnoporus sanguineus after a single exposure of Cr(VI), TBBPA and a combined exposure of TBBPA and Cr(VI), with the goal of illuminating the cellular mechanisms involved in the interactions of co-existed TBBPA and Cr(VI) with the cells of P. sanguineus at the protein level. The results revealed that some ATP-binding cassette (ABC) transporters were obviously induced by these pollutants to accelerate the transportation, transformation and detoxification of TBBPA and Cr(VI). Cr(VI) could inhibit the bioremoval of its organic co-pollutants TBBPA through suppressing the expression of several key proteins related to the metabolism of TBBPA by P. sanguineus, including two cytochrome P450s, pentachlorophenol 4-monooxygenase and glutathione S-transferases. Furthermore, Cr(VI) possibly reduced the cell vitality and growth of P. sanguineus by enhancing the expression of imidazole glycerol phosphate synthase as well as by decreasing the abundances of proteins associated with the intracellular metabolic processes, such as the tricarboxylic acid cycle, purine metabolism and glutathione biosynthesis, thereby adversely affecting the biotransformation of TBBPA. Cr(VI) also inhibited the expression of peptidyl prolyl cis/trans isomerases, thus causing the damage of cell membrane integrity. In addition, some important proteins participated in the resistance to Cr(VI) toxicity were observed to up-regulate, including heat shock proteins, 26S proteasome, peroxiredoxins and three critical proteins implicated in S-adenosyl methionine synthesis, which contributed to reducing the hazard of Cr(VI) to P. sanguineus. The results of this study provide novel insights into the physiological responses and molecular mechanism of white rot fungi P. sanguineus to the stress of concomitant TBBPA and Cr(VI).

Extracellular Polymeric Substances (EPS) influenced Poly Cyclic Aromatic Hydrocarbons (PAHs) degrading Klebsiella pneumoniae was isolated from the marine environment. To increase the EPS production by Klebsiella pneumoniae, several physicochemical parameters were tweaked such as different carbon sources (arabinose, glucose, glycerol, lactose, lactic acid, mannitol, sodium acetate, starch, and sucrose at 20 g/L), nitrogen sources (ammonium chloride, ammonium sulphate, glycine, potassium nitrate, protease peptone and urea at 2 g/L), different pH, carbon/nitrogen ratio, temperature, and salt concentration were examined. Maximum EPS growth and biodegradation of Anthracene (74.31%), Acenaphthene (67.28%), Fluorene (62.48%), Naphthalene (57.84%), and mixed PAHs (55.85%) were obtained using optimized conditions such as glucose (10 g/L) as carbon source, potassium nitrate (2 g/L) as the nitrogen source at pH 8, growth temperature of 37 °C, 3% NaCl concentration and 72 h incubation period. The Klebsiella pneumoniae biofilm architecture was studied by confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The present study demonstrates the EPS influenced PAHs degradation of Klebsiella pneumoniae.

At present, coal is considered one of the main components for the production of cheap, high-energy and environmentally attractive slurry fuels. The latter can be produced on the basis of low-grade coal dust or coal processing wastes. Thus, coal-water slurries and coal-water slurries containing petrochemicals are produced. The involvement of coal and oil processing wastes expands the scope of raw materials, reduces the fuel costs from traditional energy sources and modifies the main economic characteristics of power plant performance. However, it also increases the impact of coal-fired thermal power stations on the environment. In the last 30–50 years, many efforts have been made to decrease the negative impact of human industrial activity on climate. Involving plant-based components in the process of energy generation to save energy and material resources looks very promising nowadays. This research studies the influence of adding typical bioliquids (bioethanol, turpentine, glycerol) on the concentration of anthropogenic emissions from coal-water slurry combustion. Relative mass concentrations of bioliquids varied in a small range below 20%. We focused on the concentration of the most hazardous sulfur and nitrogen oxides from the combustion of typical filter cakes, as well as plant-containing slurries. It was established that the concentration of sulfur oxides can be decreased (as compared to coal) by 75%, whereas that of nitrogen oxides by almost 30%. Using a generalizing criteria expression, we illustrated the main benefits of adding bioliquids to slurry fuels in comparison with coal. Adding 20% of glycerol was found to provide maximum advantages.

Roxarsone (ROX), the primary aromatic arsenical additive (AAA) used in animal feeding operations, is of increasing concern to environmental and human health due to land application of ROX-laden animal manure. Few studies have investigated the phytotoxicity, uptake mechanisms, and speciation of AAA in crop plants. In this study, wheat seedlings were employed to address these issues under hydroponic conditions. Compared to inorganic arsenic, ROX was less toxic to wheat root elongation. Wheat roots were more sensitive to ROX stress than shoots. For the first time, metabolized inorganic arsenic was detected in plants, although ROX was the predominant detected arsenic species in wheat seedlings. ROX uptake and toxicity to roots were inhibited by humic acid at concentrations higher than 50 mg/L due to interaction with ROX. Phosphate enhanced ROX uptake, but no trends were observed for ROX uptake in the presence of glycerol at concentrations lower than 250 mM. In addition, ROX uptake was significantly decreased by silicate (Si(IV), 0.5–10 mM) and the metabolic inhibitor, 2,4-dinitrophenol (0.5–2 mM), indicating that ROX transport into wheat roots was actively mediated by Si(IV)-sensitive transporters. These findings provide important insights into the fate and speciation of AAA in soil-water-plant systems relevant to human health.

AsIII uptake in living cells is through aquaglyceroporin transporters, but it is unknown in arsenic-hyperaccumulator Pteris vittata. We investigated the effects of AsIII analogs glycerol and antimonite (SbIII) at 0–100 mM and aquaporin inhibitor AgNO₃ at 0–0.1 mM on the uptake of 0.1 mM AsIII or AsV by P. vittata over 1–2 h. Glycerol or SbIII didn’t impact AsIII or AsV uptake by P. vittata (p < 0.05), with As concentrations in the fronds and roots being 4.4–6.3 and 3.9–6.2 mg/kg. However, 0.01 mM AgNO₃ reduced As concentrations in the fronds and roots by 64% and 58%. Hence, AsIII uptake in P. vittata might be via an aquaporin transporter different from glycerol and SbIII transporters. Further as AsIII analogs and aquaporin inhibitor had no impact on AsV uptake, AsIII and AsV were likely taken up by different transporters in P. vittata. Our results imply a different AsIII transporter in P. vittata from other plants.

Biofilm-mediated bioremediation of xenobiotic pollutants is an environmental friendly biological technique. In this study, 36 out of 55 bacterial isolates developed biofilms in glass test tubes containing salt-optimized broth plus 2% glycerol (SOBG). Scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and Congo red- and Calcofluor binding results showed biofilm matrices contain proteins, curli, nanocellulose-rich polysaccharides, nucleic acids, lipids, and peptidoglycans. Several functional groups including –OH, N–H, C–H, CO, COO⁻, –NH₂, PO, C–O, and C–C were also predicted. By sequencing, ten novel biofilm-producing bacteria (BPB) were identified, including Exiguobacterium indicum ES31G, Kurthia gibsonii ES43G, Kluyvera cryocrescens ES45G, Cedecea lapagei ES48G, Enterobacter wuhouensis ES49G, Aeromonas caviae ES50G, Lysinibacillus sphaericus ES51G, Acinetobacter haemolyticus ES52G, Enterobacter soli ES53G, and Comamonas aquatica ES54G. The Direct Red (DR) 28 (a carcinogenic and mutagenic dye used in dyeing and biomedical processes) decolorization process was optimized in selected bacterial isolates. Under optimum conditions (SOBG medium, 75 mg L⁻¹ dye, pH 7, 28 °C, microaerophilic condition and within 72 h of incubation), five of the bacteria tested could decolorize 97.8% ± 0.56–99.7% ± 0.45 of DR 28 dye. Azoreductase and laccase enzymes responsible for biodegradation were produced under the optimum condition. UV–Vis spectral analysis revealed that the azo (−NN−) bond peak at 476 nm had almost disappeared in all of the decolorized samples. FTIR data revealed that the foremost characteristic peaks had either partly or entirely vanished or were malformed or stretched. The chemical oxygen demand decreased by 83.3–91.3% in the decolorized samples, while plant probiotic bacterial growth was indistinguishable in the biodegraded metabolites and the original dye. Furthermore, seed germination (%) was higher in the biodegraded metabolites than the parent dye. Thus, examined BPB could provide potential solutions for the bioremediation of industrial dyes in wastewater.

Arsenic (As) is a toxic pollutant that mainly enters the human body via plants. Therefore, understanding the strategy for reducing arsenic accumulation in plants is important to human health and the environment. Aquaporins are ubiquitous water channel proteins that bidirectionally transport water across cell membranes and play a role in the transportation of other molecules, such as glycerol, ammonia, boric acid, and arsenic acid. Previously, we observed that Arabidopsis PIP2;2, encoding a plasma membrane intrinsic protein, is highly expressed in NtCyc07-expressing Arabidopsis, which shows a higher tolerance to arsenite (As(III)). In this study, we report that the overexpression of AtPIP2;2 enhanced As(III) tolerance and reduced As(III) levels in yeast. Likewise, AtPIP2;2-overexpressing Arabidopsis exhibited improved As(III) tolerance and lower accumulation of As(III). In contrast, atpip2;2 knockout Arabidopsis showed reduced As(III) tolerance but no significant change in As(III) levels. Interestingly, the AtPIP2;2 transcript and protein levels were increased in roots and shoots of Arabidopsis in response to As(III). Furthermore, As(III) efflux was enhanced and As(III) influx/accumulation was reduced in AtPIP2;2-expressing plants. The expression of AtPIP2;2 rescued the As(III)-sensitive phenotype of acr3 mutant yeast by reducing As levels and slightly reduced the As(III)-tolerant phenotype of fps1 mutant yeast by enhancing As content, suggesting that AtPIP2; 2 functions as a bidirectional channel of As(III), while the As(III) exporter activity is higher than the As(III) importer activity. All these results indicate that AtPIP2;2 expression promotes As(III) tolerance by decreasing As(III) accumulation through enhancing As(III) efflux in Arabidopsis. This finding can be applied to the generation of low arsenic crops for human health.

Biodiesel side stream waste glycerol was identified as a cheap carbon source for rhamnolipids (RLs) production which at the same time could improve the management of waste. The present study aimed to produce RLs by using Pseudomonas aeruginosa RS6 utilizing waste glycerol as a substrate and to evaluate their physico-chemicals properties. Fermentation conditions such as temperature, initial medium pH, waste glycerol concentration, nitrogen sources and concentrations resulted in different compositions of the mono- and di-RLs produced. The maximum RLs production of 2.73 g/L was obtained when P. aeruginosa RS6 was grown in a basal salt medium supplemented with 1% waste glycerol and 0.2 M sodium nitrate at 35 °C and pH 6.5. At optimal fermentation conditions, the emulsification index (E₂₄) values of cooking oil, diesel oil, benzene, olive oil, petroleum, and kerosene were all above E₂₄₌50%. The surface tension reduction obtained from 72.13 mN/m to 29.4–30.4 mN/m was better than the surface activity of some chemical-based surfactants. The RLs produced possessed antimicrobial activities against Gram-negative and Gram-positive bacteria with values ranging from 37% to 77% of growth inhibition when 1 mg/mL of RLs was used. Concentrations of RLs below 1500 μg/mL did not induce phytotoxicity effects on the tested seeds (Vigna radiata) compared to the chemical-based- surfactant, SDS. Furthermore, RLs tested on zebrafish (Danio rerio) embryos only exhibited low acute toxicity with an LC₅₀ value of 72.97 μg/mL at 48 h of exposure suggesting a green and eco-biochemical worthy of future applications to replace chemical-based surfactants.