Currently, the environmental pollution is a problem that threatens the sustainability of our planet which has led to increasing scientific research in several areas to obtain sustainable biotechnologies. In this sense, the exploitation of natural-derived and renewable biopolymers as a replacement for petrochemical-derived polymers, confining the use of synthetic polymers, has received visibility and interest for applications in biomedical materials and / or in bioremediation Microbial extracellular polymeric substances (EPS) from cyanobacteria and bacteria have displayed a promising potential as alternative to synthetic resources. They can be used in numerous applications in the biomedical fields, such as scaffolds or matrices in tissue engineering, drug delivery and wound dressing, and in bioremediation fields for the removal of organic and metallic pollutants. However, the symbiotic association between cyanobacteria and cellulose- producing bacteria to obtain biofunctional materials has not been exploited. In this research work, these association will be study through two approaches: (i) bacterial cellulose will be biosynthesized in the presence of the cyanobacteria to include in situ the algal exopolymers and functional compounds in their network and (ii) obtain microcapsules and bioactive films through the inclusion of exopolymers and/or bioactive compounds in bacterial cellulose by bioencapsulation and 3D printing processes. These biomaterials can be used for future applications and for the design of sustainable biofunctional materials, capable of replacing the current synthetic materials.

Greenhouses are needed in hot climates to protect plants from excessive heat, which limits productivity, and to reduce the excessive energy and water requirements associated with controlled environment agriculture under such conditions. In arid climatic regions, where ambient air temperature can easily reach 60°C during the summer and where fresh water is scarce, a new approach to greenhouse design should be used to make it more economically feasible. The approach is to use passive, as well as active, energy conservation measures, aimed mainly to reduce the cooling load in an arid climate. Conventional air cooling systems do not only increase the total energy consumption resulting in large carbon footprint, but also raise the peak load demand on power causing excessive strains on the power grid. Heat-driven air cooling systems that use solar energy are now emerging as alternatives to the electricity-driven refrigerated air coolers. These systems are found to be more energy efficient, with lower carbon emissions while also ensuring better indoor air quality and comfort when optimally designed. The concept is to reduce the amount of intense solar radiation as well as save power consumed for air conditioning the greenhouses. This is achieved in this study via coating greenhouses with polymer aerogel. Aerogel is a lightweight solid derived from gel in which the liquid component of the gel has been replaced with air and makes aerogel extremely low density with low thermal conductivity. Because of these unique properties, aerogel is considered one of the most efficient insulating materials. At a low temperature, radiation is not a significant problem for transparent material. However, at a high temperature, radiative transport is dominant for thermal conduction and this causes energy and thermal performance of greenhouses to improve significantly when coated with aerogels.

Drilling muds are one of the most important components of drilling operations. They are suspension of solids in either water or oil, which can be mixed with other substances, called additives. The drilling fluid functions should be optimized to ensure safety and minimum whole problems which are extremely costly in terms of materials and time. There are several additives used to ensue getting the appropriate functions of drilling fluids. The incorporation of the additives confirmed to reduce the loss of fluid into the formation, minimize pipe sticking, minimize losses in pressure, increase rate of penetration, reduce environmental impact and improve safety. Oil and gas drilling industry uses huge amounts of chemicals in drilling fluids as additives. Most of these chemicals are toxic and pose an excessive threat to mankind as well as the environment. On a global level, regulations to minimize utilization of toxic materials as drilling fluid components have been set to eliminating the environmental impact of expensive drilling fluid additives. The current work investigates the feasibility of using a bio-degradable waste (Barely grass) as green drilling fluid additive. The combined effect of barely grass concentration (0.29-1.7g) and bentonite (12.9-27.1g) is evaluated according to an adopted experimental design. The rheological and filtration properties were measured and compared to a reference fluid. The average range of apparent viscosity, plastic viscosity, yield point, and low-shear-rate yield point for the prepared drilling muds are 7.5-27 cP, 5-13 cP, 5-42 lb/100ft2, and 2-23 lb/100ft 2 respectively. The mathematical models and the variables significance are estimated from response surface analysis. The optimized drilling mud has competitive rheological and filtration characteristics compared to reference fluid. The additive seemed promising alternative to commercial polymer additives owing to its high fibers content mostly polysaccharides.

Currently, microplastics (MPs) are an issue of concern for marine ecosystems and biota due to their bioaccumulation and biomagnification with other pollutants. It has become urgent to develop sustainable and effective methods to remove them from the contaminated water. Cellulosic banana pulp and extracellular polymeric substances (EPS) – produced by microorganisms (cyanobacteria and bacteria) – are recognized as biodegradable, sustainable and low toxic materials, making them promise for applications in a wide range of fields - from biomedicine to bioremediation [1,2]. EPS are currently widely applied in industry as gums, bioflocculants, biosorbents and bioemulsifiers [3]. The present study intended to evaluate the feasibility of using cellulosic banana pulp per si – an agricultural residue – or nanomodified with EPS from cyanobacteria and bacteria for the removal of MPs from contaminated water. Banana pseudo-stem pulping was used as biofilter per si or nanomodified with (i) Cyanocohniella calida culture, (ii) C. calida EPS and (iii) bacterial cellulose pulp, through two processes: incorporation and immersion. A contaminated water solution with polystyrene MPs was used. The removal of MPs via biofilters was assessed by fluorescence microscopy, Neubauer chamber and flow cytometry. It was observed that the MPs were retained in the biofilter network. The efficiency limits of biofilters were also evaluated. Biofilters per si showed high efficiency (98.5%) in removing MPs from contaminated water. The retention capacity of microplastics increases with the increase amount of cellulose fibers. Nanomodified biofilter also exhibited a high removal efficiency (86.8%) when modified with 20% (m/v) C. calida EPS by immersion. The results show that the use of biofilters based on pulp of banana, given its durability and MPs holding capacity, could be an environmentally friendly alternative to commercial filters. This eco-technology proved to be an alternative for water decontamination.

The determination of the superficial characteristics of solid substrates and more particularly of polymers or polymers adsorbed on oxides is of capital importance to the comprehension and the forecast of their behaviors in many applications. These solid surfaces are generally in contact with gas, liquids or other solids, such as for example association polymer/metallic oxides for the coatings of paintings or industrial packing. Acrylate polymers as poly methyl methacrylate (PMMA) or poly (α-n-alkyl) methacrylate are preferentially used in various fields such as architecture, aeronautics, urban furniture, electronics, etc. In this paper, inverse gas chromatography (IGC) at infinite dilution was applied in order to determine the change, as related to temperature, of the properties and the second order transitions of some polymers adsorbed on oxides, and particularly to study the transition phenomena of poly (α-n-alkyl) methacrylate adsorbed on silica or alumina. The study of the evolution of RTlnVn, as a function of 1/T for different n-alkanes adsorbed on poly (α-n-alkyl) methacrylates, allowed to an accurate determination of their transition temperature (Tg). The dispersive energy and the acid base properties in the Lewis terms of poly (α-n-alkyl) methacrylates were determined. The acid base constants KA and KD of various polymers were calculated by testing both the classical and Hamieh models. It was proved an important effect of the length of alkyl group in side chain of poly (α-n-alkyl) methacrylates on the surface properties of such polymers and especially on the acid base constants and the transition phenomena. It was also proved an excellent linear correlation between the specific enthalpy of adsorption, the acid base constants, the carbon atom number in the side chain of poly(a-n-alkyl) methacrylates and the acceptor AN and donor DN numbers of electrons of polar organic molecules.