In this research, polyvinyl alcohol (PVA) was mixed with clay nanoparticles with weight ratios of 1, 3, or 5 wt%
to form PVA/clay composites using the solvent casting method for food packaging uses. Chemical bonds and
function groups were identified using Fourier transform infrared spectroscopy, while mechanical parameters e.g.
tensile strength (Ts), elongation (Eb), and Young modulus (Ym) of the synthesized PVA/clay film were examined.
Other characteristics were studied and discussed such as water uptake (swelling and porosity), contact angle,
optical qualities (transmission, brightness), barrier properties i.e. water vapor transfer rate, and antimicrobial
performance. The addition of clay nanoparticles raised Ym from 1.3 MPa to 2.9 MPa, while decreasing Ts and Eb
from 77 MPa and 3.8 % to 59 MPa and 3.6 %, respectively. Also, incorporating clay nanoparticles reduces water
absorption, moisture level, transmission, and brightness while improving the thermal conductivity and water
vapor transport rates of PVA. Furthermore, the incorporation of clay nanoparticles improves thermal, mechanical,
optical, and antibacterial performance, which could be beneficial for food packaging applications.

In this study, long-range van der Waals (vdW) and effective Coulomb interaction (Ueff) corrected density functional theory (DFT + vdW + Ueff) calculations were performed to explore the effect of co-doping (of Co and Sn) on the crystal structure, electronic, magnetic and chemical (H2 adsorption) properties of phosphorene. The stability of the doped structures was determined with formation energy (Ef) and molecular dynamics (MD) simulations. The dopants were found to form strong bonds with phosphorus (P) atoms. The introduction of Co/Sn-atoms slightly altered the local geometry of phosphorene, resulting in new electronic characteristics. For instance, unlike pristine phosphorene (P48), the co-doped phosphorene (P45CoxSny) can exhibit ferrimagnetic (FIM) or ferromagnetic (FM) coupling in the ground state. The doped structures exhibit integral magnetic moments, mainly contributed by the Co-atoms. The P45Co1Sn2 and P45Co2Sn1 structures show metallic band structure, while P45Co3 becomes a small band gap (Eg) semiconductor (Eg =0.2 eV). The adsorption of the H2 molecules was investigated at various sites on un-doped and co-doped phosphorene. It was found that H2 molecule is weakly adsorbed on un-doped phosphorene, whereas moderate adsorption was observed for co-doped systems. The adsorption energy (Ea) was found to be -0.03, -0.35, -0.48, and − 0.65 eV, respectively for P48, P45Co1Sn2, and P45Co2Sn1 and P45Co3. The DOS plots confirmed that the observed adsorption is due to the s-d interaction between H-atom and the doped Co-atom. The Bader charge and charge density difference (CDD) analysis showed that H2 molecule acts as a charge acceptor and doped phosphorene as a charge donor. In addition, the effect of strain on adsorption was also considered. The adsorption capacity of the doped systems decreased with the number of H2 molecules. These findings show that co-doped phosphorene can be used for spin-based nanodevices and hydrogen capture for energy storage applications.

There is an upsurge need for bioplastics as a sustainable and eco-friendly alternative to petroleum-based plastics. Algae polysaccharides such as alginate, carrageenan, agar, starch, ulvan, porphyran, fucoidan, and cellulose are promising candidates for the development of biobased plastics. Similarly, macromolecules such as polyhydroxyalkanoates and proteins could be utilized in bioplastic preparation. These bioplastics have been exploited in the food industry, medicine, water treatment and desalination, and agriculture. In these fields, bioplastics are mainly applied as food coatings, packages, drug-delivery materials, wound dressings, adsorbents, filters, mulching films and membranes for fuel cells and batteries, etc. This chapter provides a general overview on recent advances and applications of bioplastics derived from algae polymers and composites.

Currently, the need to use renewable feedstocks for bioenergetic purposes is an urgent demand due to the depletion of fossil fuels. Microalgae have been utilized as a resilient and a cost-effective source for biofuel production since they can be cultivated using wastewater without the need for fertile soil and are characterized by a fast cell growth rate, and effective CO₂ sequestration. The additional benefit of microalgae includes a high yield of industrially important components such as pigments, lipids, carbohydrates, proteins, and secondary metabolites. The simultaneous production of these components during biofuel production in a biorefinery process makes microalgae a promising feedstock to be more economically feasible. This chapter discusses various cultivation conditions, harvesting, and biofuel production techniques. Furthermore, the cost of biofuel production could be reduced by different upstream processes by selecting the high producing strains as well as downstream processes through enhancing biofuel yields and advanced processes for converting biomass to biofuels. Processes for the production of biodiesel, extraction of lipids, transesterification, hydrothermal liquefaction, and pyrolysis will also be discussed. This chapter also highlights the challenges behind biofuel production based on algal biomass, as well as the future perspectives.

Intracellular hyperaccumulation of phycocyanin (PC) and its high susceptibility to degradation at higher temperatures are major challenging problems associated with its production from cyanobacteria. The present study evaluated different concentrations of organic acids (1, 2, and 3 mM) (citric acid, acetic acid, succinic acid, fumaric acid, and oxalic acid) under fed-batch mode on the biomass and phycobiliproteins’ production from Arthrospira platensis. Besides they were evaluated at 2.5–7.5 mM as preservative to stabilize PC at high temperatures. The incorporation of 3 mM of succinic acid into the cultivation medium enhanced the biomass and PC productivity to 164.05 and 26.70 mg L⁻¹ day⁻¹, which was ~ 2- and threefold higher than control, respectively. The produced PC in this treatment was food-grade with a 2.2 purity ratio. The use of organic acids also enhanced the thermal stability of PC. Citric acid (7.5 mM) markedly promoted the half-life values of PC to 189.44 min compared to 71.84 min in the control. The thermodynamic analysis confirmed higher thermostability of PC in the presence of organic acids and indicated the endothermic and non-spontaneity of the thermal denaturation process. The findings of the present study confirmed that organic acids could be utilized as cost effective and sustainable compounds for promoting not only phycobiliproteins’ production but also the thermostability of PC for potential application in food industry.