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Low-density polyethylene (LDPE) waste generates an environmental impact. To achieve the most suitable option for their degradation, it is necessary to implement chemical, physical and biological treatments, as well as combining procedures. Best treatment was prognosticated by Plackett-Burman Experimental Design (PB), evaluating five factors with two levels (0.25 mM or 1.0 gL-1 glucose, 1.0 or 2.0 mM CuSO4, 0.1 or 0.2 mM ABTS [2, 20-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)], pH 4.5 ± 0.2 or 7.0 ± 0.2 and 30 or 90 day incubation), which was reproduced for 150 days. Therefore, PB identified a sequential treatment (plasma followed by fungus) for partial LDPE biodeterioration. Sheets were pretreated with glow discharge plasma (O2, 3.0 x 10−2 mbar, 600 V, 6 min.), followed by Pleurotus ostreatus biodeterioration. Fungus growth, colonization percentage, and pigment generation followed. Laccase (Lac), manganese peroxidase (MnP) and lignin peroxidase (LiP) activities were appraised. Additionally, contact angle (CA), functional group presence and changes and carbonyl and vinyl indices (Fourier transformed infrared spectroscopy) were evaluated. LDPE surface changes were assessed by Young’s modulus, yield strength, scanning electronic microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Plasma discharge increased hydrophilicity, decreasing CA by 76.57% and increasing surface roughness by 99.81%. P. ostreatus colonization was 88.72% in 150 days in comparison with untreated LDPE (45.55%). After this treatment carbonyl groups (C = O), C = C insaturations, high hydrophilicity CA (16 ± 4) °, and low surface roughness (7 ± 2) nm were observed. However, the highest Lac and LiP activities were detected after 30 days (Lac: 2.817 U Lac g-1 and LiP: 70.755 U LiP g-1). In addition, highest MnP activity was observed at day 120 (1.097 U MnP g-1) only for P. ostreatus treated LDPE. Plasma favored P. ostreatus adsorption, adherence, growth and colonization (88.72%), as well as partial LDPE biodeterioration, supported by increased hydrophilicity and presence of specific functional chemical groups. The approximate 27% changes in LDPE physical properties support its biodeterioration.

A simultaneous treatment of lignocellulosic biomass (LCB) and low density oxodegradable polyethylene (LDPE oxo ) was carried-out using Pleurotus ostreatus at microcosm scale to obtain biotransformed plastic and oxidized lignocellulosic biomass. This product was used as raw matter (RM) to produce biochar enriched with phosphate solubilizing bacteria (PSB). Biochar potential as biofertilizer was evaluated in Allium cepa culture at greenhouse scale. Experiments including lignocellulosic mix and LDPE oxo were performed for 75 days in microcosm. Biotransformation progress was performed by monitoring total organic carbon (TOC), CO 2 production, laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP) enzymatic activities. Physical LDPE oxo changes were assessed by atomic force microscopy (AFM), scanning electron microscopy (SEM) and static contact angle (SCA) and chemical changes by Fourier transform infrared spectroscopy (FTIR). Results revealed P . ostreatus was capable of LCB and LDPE oxo biotransformation, obtaining 41% total organic carbon (TOC) removal with CO 2 production of 2,323 mg Kg -1 and enzyme activities of 169,438 UKg -1 , 5,535 UKg -1 and 5,267 UKg -1 for LiP, MnP and Lac, respectively. Regarding LDPE oxo , SCA was decreased by 84%, with an increase in signals at 1,076 cm -1 and 3,271 cm -1, corresponding to C-O and CO-H bonds. A decrease in signals was observed related to material degradation at 2,928 cm -1 , 2,848 cm -1 , agreeing with CH 2 asymmetrical and symmetrical stretching, respectively. PSB enriched biochar favored A . cepa plant growth during the five-week evaluation period. To the best of our knowledge, this is the first report of an in vitro circular production model, where P . ostreatus was employed at a microcosmos level to bioconvert LCB and LDPE oxo residues from the agroindustrial sector, followed by thermoconversion to produce an enriched biochar with PSB to be used as a biofertilizer to grow A . cepa at greenhouse scale.

The history of colour is fascinating from a social and artistic viewpoint because it shows the way; use; and importance acquired. The use of colours date back to the Stone Age (the first news of cave paintings); colour has contributed to the social and symbolic development of civilizations. Colour has been associated with hierarchy; power and leadership in some of them. The advent of synthetic dyes has revolutionized the colour industry; and due to their low cost; their use has spread to different industrial sectors. Although the percentage of coloured wastewater discharged by the textile; food; pharmaceutical; cosmetic; and paper industries; among other productive areas; are unknown; the toxic effect and ecological implications of this discharged into water bodies are harmful. This review briefly shows the social and artistic history surrounding the discovery and use of natural and synthetic dyes. We summarise the environmental impact caused by the discharge of untreated or poorly treated coloured wastewater to water bodies; which has led to physical; chemical and biological treatments to reduce the colour units so as important physicochemical parameters. We also focus on laccase utility (EC 1.10.3.2), for discolouration enzymatic treatment of coloured wastewater, before its discharge into water bodies. Laccases (p-diphenol: oxidoreductase dioxide) are multicopper oxidoreductase enzymes widely distributed in plants, insects, bacteria, and fungi. Fungal laccases have employed for wastewater colour removal due to their high redox potential. This review includes an analysis of the stability of laccases, the factors that influence production at high scales to achieve discolouration of high volumes of contaminated wastewater, the biotechnological impact of laccases, and the degradation routes that some dyes may follow when using the laccase for colour removal

Lacasses are multicopper oxidases that can catalyze aromatic and non-aromatic compounds concomitantly with reduction of molecular oxygen to water. Fungal laccases have generated a growing interest due to their biotechnological potential applications, such as lignocellulosic material delignification, biopulping and biobleaching, wastewater treatment, and transformation of toxic organic pollutants. In this work we selected fungal genes encoding for laccase enzymes GlLCC1 in Ganoderma lucidum and POXA 1B in Pleurotus ostreatus. These genes were optimized for codon use, GC content, and regions generating secondary structures. Laccase proposed computational models, and their interaction with ABTS [2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] substrate was evaluated by molecular docking. Synthetic genes were cloned under the control of Pichia pastoris glyceraldehyde-3-phosphate dehydrogenase (GAP) constitutive promoter. P. pastoris X-33 was transformed with pGAPZαA-LaccGluc-Stop and pGAPZαA-LaccPost-Stop constructs. Optimization reduced GC content by 47 and 49% for LaccGluc-Stop and LaccPost-Stop genes, respectively. A codon adaptation index of 0.84 was obtained for both genes. 3D structure analysis using SuperPose revealed LaccGluc-Stop is similar to the laccase crystallographic structure 1GYC of Trametes versicolor. Interaction analysis of the 3D models validated through ABTS, demonstrated higher substrate affinity for LaccPost-Stop, in agreement with our experimental results with enzymatic activities of 451.08 ± 6.46 UL-1 compared to activities of 0.13 ± 0.028 UL-1 for LaccGluc-Stop. This study demonstrated that G. lucidum GlLCC1 and P. ostreatus POXA 1B gene optimization resulted in constitutive gene expression under GAP promoter and α-factor leader in P. pastoris. These are important findings in light of recombinant enzyme expression system utility for environmentally friendly designed expression systems, because of the wide range of substrates that laccases can transform. This contributes to a great gamut of products in diverse settings: industry, clinical and chemical use, and environmental applications.

Different genus of bacteria has been reported with the capacity to solubilize phosphorus from phosphate rock (PR). Pseudomonas sp., (A18) and Serratia sp., (C7) isolated from soils at the “ Departamento de Boyacá ” Colombia, where Allium cepa is cultivated. Bacteria were cultured in MT11B media and evaluated as a bio-fertilizer for A. cepa germination and growth during two months at greenhouse scale. Pseudomonas sp., and Serratia sp., cultured at 30 °C, 48 h in SMRS1 agar modified with PR, (as an inorganic source of phosphorus), presented a phosphate solubilization index (SI) of 2.1 ± 0.2 and 2.0 ± 0.3 mm, respectively. During interaction assays no inhibition halos were observed, demonstrating there was no antagonism between them. In MT11B media growth curve (12 h) demonstrated that co-culture can grow in the presence of PR and glucose concentrations 7.5-fold, lower than in SMRS1 media and brewer's yeast hydrolysate; producing phosphatase enzymes with a volumetric activity of 1.3 ± 0.03 PU at 6 h of culture and 0.8 ± 0.04 PU at 12 h. Moreover, co-culture released soluble phosphorus at a rate of 58.1 ± 0.28 mg L −1 at 8 h and 88.1 ± 0.32 mg L −1 at 12 h. After five days of evaluation it was observed that germination percentage was greater than 90 % of total evaluated seeds, when placing them in contact with the co-culture in a concentration of 1 × 10 8 CFU mL −1 . Furthermore, it was demonstrated that co-culture application (10 mL per experimental unit to complete 160 mL in two months) at 8.0 Log 10 CFU mL −1 twice a week for two months increased A. cepa total dry weight (69 ± 13 mg) compared with total dry weight (38 ± 5.0 mg) obtained with the control with water.

The adsorption performance of a Cu-TiO2composite for removing acid blue 80 (AB80) dye from aqueous solutions was investigated in terms of kinetics, equilibrium, and thermodynamics. The effect of operating variables, such as solution pH, initial dye concentration, contact time, and temperature, on AB80 adsorption was studied in batch experiments. AB80 adsorption increased with increasing contact time, initial dye concentration, and temperature and with decreasing solution pH. Modeling of adsorption kinetics showed good agreement of experimental data with the pseudo-second-order kinetics model. The experimental equilibrium data for AB80 adsorption were evaluated for compliance with different two-parameter, three-parameter, and four-parameter isotherm models. The Langmuir isotherm model best described the AB80 adsorption equilibrium data. The thermodynamic data revealed that the AB80 adsorption process was endothermic and nonspontaneous. Kinetics, equilibrium, and thermodynamic results indicate that Cu-TiO2adsorbs AB80 by a chemical sorption reaction.

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