Life cycle assessment of a technology is the key to technological development in the context of sustainable development. Orchard waste has been identified as a potential source of bioplastics. The objective of this study was to conduct a life cycle assessment of two specific bioplastic materials, namely, L-polylactic acid (PLA) and poly(3-hydroxybutyrate) (PHB). Bioplastics, such as PLA acid and PHB, can be used as alternatives to conventional plastics due to their biodegradability and non-toxicity, both of which have the potential to replace conventional petroleum-based plastics. Polylactic acid was synthesized from orchard waste in a series of stages, including biomass processing, pretreatment for carbohydrate extraction, simultaneous saccharification and fermentation (SSF), and microwave polymerization. PHB, another biodegradable polymer, is produced by microorganisms through the fermentation of sugars obtained from the same biomass. Applied LCAs show that for PLA production, the stages having the greatest environmental impact are biomass processing, pretreatment, and the SSF process, and for PHB production, very energy-intensive stages significantly contributing to the environmental impacts are biomass processing and pretreatment stages. For both PLA and PHB, the initial stages of biomass processing and pretreatment are the most energy-intensive and significant contributors to CO₂ emissions.

Bone regeneration has gained attention in the biomedical field, which has led to the development of materials and synthesis methods meant to improve osseointegration and cellular bone activity. The properties of hydroxyapatite, a type of calcium phosphate, have been researched to determine its advantages for bone tissue engineering, particularly its biocompatibility and ability to interact with bone cells. Recently, the advantages of utilizing nanomolecules of hydroxyapatite, combined with various substances, in order to enhance and combine their characteristics, have been reported in the literature. This review will outline the cellular and molecular roles of hydroxypatite, its interactions with bone cells, and its nano-combinations with various ions and natural products and their effects on bone growth, development, and bone repair.

Biofuels, as a renewable, eco-friendly, and cost-effective energy source, can reduce the dependence on fossil fuels. The researchers considered different approaches for obtaining high biodiesel yields from microalgae biomass. This work aims to present an overview of the feasibility of microalgae use in biodiesel production. Therefore, biodiesel production from microalgae oil via the transesterification process was explained in detail. The application of non-catalytic transesterification and catalytic transesterification was reviewed. The achievements in the application of homogenous catalysts, heterogeneous catalysts, and enzymatic catalysts for microalgae oil transesterification were discussed. The present technologies for biodiesel production from microalgae need more improvements to increase their efficiencies and reduce costs. Therefore, future research should focus on the development of effective catalysts for biodiesel production from microalgae biomass.

Globally, as the population and the living standards expanded, so did the use of energy and materials. Renewable energy resources are being used to help address the energy issue and reduce greenhouse gas emissions (GHG). Because lignocellulosic biomass resources are widely available and renewable, various processes are used to convert these resources into bioenergy. In the current study, two production processes were evaluated, namely the transformation of vine shoot waste into value-added biofuels, i.e., pellets/briquettes and bioethanol. The life cycle assessment (LCA) technique was used for simulating and documenting the environmental performance of two biomass waste to biofuels pathways, possible candidates for closing loops in the viticulture production, according to the circular economy models. The SimaPro software was used to perform the LCA. The results show that the pellets/briquettes production process has a lower negative influence on the studied environmental impact categories compared to the production of bioethanol.

Vineyards waste has a great importance as biomass, a renewable source of energy. In this paper eight vine shoot varieties were used for the production of pellets by densification of feedstock materials with four ranges of moisture contents (6–8%, 8–10%, 10–12% and 12–15%). A moisture content of 10% gave durability higher than 97.5% and a calorific value greater than 17 MJ kg⁻¹ and the small durability was obtained for 6–8% moisture. The study shows the significant influence of water during densification. The physicochemical and energetic properties of pellets were evaluated in accordance with ISO 17225-6 (2014). The obtained pellets were also structurally characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). SEM analysis showed the formation of carbon microsphere after pelletization, due to the increase of bulk density and durability of pellets. Also, XRD analysis revealed the crystallinity of cellulose, while TGA analysis showed a total decomposition of pellets. The obtained pellets were burned in a domestic boiler and the flue gases were measured. The preliminary results showed that the vineyard residues had higher emissions, but below the admitted limits, with the exception of carbon monoxide content. The obtained results suggested that the biomass wastes can be used for the production of pellets, aiming to enhance the research for the manufacturing of these sustainable biofuels with some remarks regarding risk of corrosion and slag formation during prolonged use.

Microalgae are among the most promising feedstocks for a wide range of applications due to their ease of cultivation, rapid growth rate, and ability to accumulate significant amounts of lipids and other valuable compounds. In the current study, two microalgae species, Chlorella sp. and Spirulina platensis, were studied regarding chemical composition, lipid extraction by ultrasound-assisted solvent extraction, and volatile compounds analysis. The optimization of the lipid extraction process was investigated with respect to the influence of different process parameters. The highest lipid content was found in Chlorella sp., which was more than twice as high compared to Spirulina platensis. Both microalgae contain saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs). Spirulina platensis contains high palmitic acid (42.9%) and linolenic acid (22.5%), and is low in MUFA content (8.5%), whereas Chlorella sp. contains high oleic (21.9%), linoleic (25.3%), and α-Linolenic acid (10.2%). Based on the fatty acids profile, nutritional lipid indices were calculated. Regarding the volatile content, Spirulina platensis contains amines, aldehydes, alcohols, ketones, and hydrocarbons, whereas Chlorella sp. contains hydrocarbons, heterocycle, aldehydes, thiocyanates, and esters which give the odor profile.