Green synthesis, based on green chemistry, is replacing the traditional methods, aiming to contribute with an enhanced environmental sustainability, which can be achieved using nontoxic compounds from biological resources, such as natural extracts from plants. In this study, the life cycle assessment (LCA) of iron oxide nanoparticles prepared through the green synthesis and the coprecipitation method is reported by following a cradle-to-gate approach. The LCA allowed quantifying and normalized the environmental impacts produced by the green synthesis (1.0 × 10^–9), which used a Cymbopogon citratus (C. citratus) extract and sodium carbonate (Na₂CO₃). The impacts were also determined for the coprecipitation method (1.4 × 10^–8) using the iron(II) salt precursor and sodium hydroxide (NaOH). The contribution of C. citratus extract and Na₂CO₃ as the precursor and pH-stabilizing agents, respectively, was compared regarding the iron(II) and NaOH compounds. Environmental sustainability was evaluated in human toxicity, ecosystem quality, and resource depletion. The major environmental contribution was found in the marine aquatic ecotoxicity (7.6 × 10^–10 and 1.22 × 10^–8 for green synthesis and the coprecipitation method) due to the highest values for ethanol (3.5 × 10^–10) and electricity (1.4 × 10^–8) usage since fossil fuels and wastewater are involved in their production. The C. citratus extract (2.5 × 10^–12) presented a better environmental performance, whereas Na₂CO₃ (4.3 × 10^–11) showed a slight increase contribution compared to NaOH (4.1 × 10^–11). This is related to their fabrication, involving toxic compounds, land occupation, and excessive water usage. In general, the total environmental impacts are lower for the green synthesis, suggesting the implementation of environmentally friendlier compounds based on natural sources for the production of nanomaterials.

Synthetic food colourants are widely used in the food industry, but consumer concerns about safety and sustainability are driving a need for natural food-colour alternatives. Betanin, which is extracted from red beetroots, is a commonly used natural red food colour. However, the betanin content of beetroot is very low (~0.2% wet weight), which means that the extraction of betanin is incredibly wasteful in terms of land use, processing costs and vegetable waste. Here we developed a sustainability-driven biotechnological process for producing red beet betalains, namely, betanin and its isomer isobetanin, by engineering the oleaginous yeast Yarrowia lipolytica. Metabolic engineering and fermentation optimization enabled production of 1,271 ± 141 mg l⁻¹ betanin and 55 ± 7 mg l⁻¹ isobetanin in 51 h using glucose as carbon source in controlled fed-batch fermentations. According to a life cycle assessment, at industrial scale (550 t yr⁻¹), our fermentation process would require significantly less land, energy and resources compared with the traditional extraction of betanin from beetroot crops. Finally, we apply techno-economic assessment to show that betanin production by fermentation could be economically feasible in the existing market conditions.

New ways and technologies for synthesizing adsorbent materials have been emerging based on the green chemistry concept for the sustainable use of available resources. In this sense, the chitosan-based products arise as a promising technology alternative for application of several fields that include mitigation, prevention, and control of environmental issues. Nevertheless, there is a lack of information about the development and behavior of these topologies at the industrial scale. This study addressed the techno-economic and sensitivity analyses as decision-making tools to assess promising topologies for production of chitosan-based bio-adsorbents. From the data provided by process inventory, economic analysis of these routes was implemented. The evaluation allowed obtaining a start point market price for chitosan microbeads (64.40 $/t) and chitosan microbeads modified with TiO₂ nanoparticles (37 $/t). The economic analysis also showed that there is a vast potential to explore the chitosan market that enables generation of very profitable businesses from the implementation of those processes, considering the obtained economic performance indicators for both topologies. It is crucial to highlight that these indicators were slightly higher for chitosan microbead production. In addition, the sensitivity analysis indicated that the chitosan-TiO₂ process could resist higher fluctuations in the operating costs, which might indicate that this topology might be a reliable alternative between evaluated cases.

Nanoparticles are materials with special properties that can be applied in different fields, such as medicine, engineering, food industry and cosmetics. The contributions regarding the synthesis of different types of nanoparticles have allowed researchers to determine a special group of nanoparticles with key characteristics for several applications. Magnetite nanoparticles (Fe₃O₄) have attracted a significant amount of attention due to their ability to improve the properties of polymeric materials. For this reason, the development of novel/emerging large scale processes for the synthesis of nanomaterials is a great and important challenge. In this work, an environmental assessment of the large scale production of magnetite via coprecipitation was carried out with the aim to evaluate its potential impact on the environment at a processing capacity of 806.87 t/year of magnetite nanoparticles. The assessment was performed using a computer-aided tool based on the Waste Reduction Algorithm (WAR). This method allows us to quantify the impacts generated and classify them into eight different categories. The process does not generate any negative impacts that could harm the environment. This assessment allowed us to identify the applicability of the large scale production of magnetite nanoparticles from an environmental viewpoint.