Environmental contamination, extensive exploitation of fuel sources and accessibility of natural renewable resources represent the premises for the development of composite biomaterials. These materials have controlled properties, being obtained through processes operated in mild conditions with low costs, and contributing to the valorization of byproducts from agriculture and industry fields. A novel board composite including lignocelullosic substrate as wheat straws, fungal mycelium and polypropylene embedded with bacterial spores was developed and investigated in the present study. The bacterial spores embedded in polymer were found to be viable even after heat exposure, helping to increase the compatibility of polymer with hydrophilic microorganisms. Fungal based biopolymer composite was obtained after cultivation of Ganoderma lucidum macromycetes on a mixture including wheat straws and polypropylene embedded with spores from Bacillus amyloliquefaciens. Scanning electron microscopy (SEM) and light microscopy images showed the fungal mycelium covering the substrates with a dense network of filaments. The resulted biomaterial is safe, inert, renewable, natural, biodegradable and it can be molded in the desired shape. The fungal biocomposite presented similar compressive strength and improved thermal insulation capacity compared to polystyrene with high potential to be used as thermal insulation material for applications in construction sector.

According to literature data, different micro- and nanopowders have been used as a partial substitute for cement mortar due to their small size and large specific surface area. The aim of the work is to develop innovative materials based on cement mortar with antibacterial and self-cleaning properties, which can be used in the long-term maintenance of clean spaces. First, zinc oxide/hydroxyapatite (ZnO/Hap) powder denoted as ZH was synthesized by the hydrothermal method; then it was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM)/ energy dispersive spectroscopy (EDS), and adsorption–desorption isotherms. The second step was the cement mortar preparation: one plain, denoted E, and one with ZH powder inside, denoted MZH. Both mortars were subjected to self-cleaning and antibacterial tests. In the self-cleaning tests, two concentrated solutions of rhodamine B and methylene blue were used. MZH showed a better decolorating after 24 h of UV light than plain cement mortar denoted E for both solutions. In order to highlight the antibacterial effect of cement mortars on some strains of Gram-positive and Gram-negative bacteria, the direct contact method was used. The study revealed that, after 24 h of incubation, the planktonic growth of the E. coli strain is significantly inhibited in the presence of the MZH sample, compared to the control strain. MZH cement mortar exhibits a better growth inhibitory property than the plain cement mortar E.

Biomineralization, the use of microorganisms to produce calcium carbonate, became a green solution for application in construction materials to improve their strength and durability. The calcifying abilities of several bacteria were investigated by culturing on a medium with urea and calcium ions. The characterization of the precipitates from bacterial cultures was performed using X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The formation of carbonate crystals was demonstrated by optical and scanning electron microscopy. Water absorption and compressive strength measurements were applied to mortars embedded with sporal suspension. The efficiency of the supplementation of mortar mixtures with bacterial cells was evaluated by properties, namely the compressive strength and the water absorption, which are in a relationship of direct dependence, the increase in compressive strength implying the decrease in water absorption. The results showed that Bacillus subtilis was the best-performing bacterium, its introduction into the mortar producing an increase in compressive strength by 11.81% and 9.50%, and a decrease in water absorption by 11.79% and 10.94%, after 28 and 56 days of curing, respectively, as compared to standards. The exploitation of B. subtilis as a calcifying agent can be an interesting prospect in construction materials.

Concrete is the most used construction material, but its industrial production from lime consumes 2–3% of the global energy demand, generating 0

Concrete is the most used construction material, but its industrial production from lime consumes 2–3% of the global energy demand, generating 0

The conservation-restoration interventions at historical monuments in Romania require