Microalgae-mediated biofixation as an innovative technology for flue gases towards carbon neutrality: A comprehensive review.

Microalgae-mediated industrial flue gas biofixation has been widely discussed as a clean alternative for greenhouse gas mitigation. Through photosynthetic processes, microalgae can fix carbon dioxide (CO2) and other compounds and can also be exploited to obtain high value-added products in a circular economy. One of the major limitations of this bioprocess is the high concentrations of CO2, sulfur oxides (SOx), and nitrogen oxides (NOx) in flue gases, according to the origin of the fuel, that can inhibit photosynthesis and reduce the process efficiency. To overcome these limitations, researchers have recently developed new technologies and enhanced process configurations, thereby increased productivity and CO2 removal rates. Overall, CO2 biofixation rates from flue gases by microalgae ranged from 72 mg L-1 d -1 to over 435 mg L-1 d-1, which were directly influenced by different factors, mainly the microalgae species and photobioreactor. Additionally, mixotrophic culture have shown potential in improving microalgae productivity. Progress in developing new reactor configurations, with pilot-scale implementations was observed, resulting in an increase in patents related to the subject and in the implementation of companies using combustion gases in microalgae culture. Advancements in microalgae-based green technologies for environmental impact mitigation have led to more efficient biotechnological processes and opened large-scale possibilities.

Microbial Bioherbicides Based on Cell-Free Phytotoxic Metabolites: Analysis and Perspectives on Their Application in Weed Control as an Innovative Sustainable Solution.

Weeds cause significant agricultural losses worldwide, and herbicides have traditionally been the main solution to this problem. However, the extensive use of herbicides has led to multiple cases of weed resistance, which could generate an increase in the application concentration and consequently a higher persistence in the environment, hindering natural degradation processes. Consequently, more environmentally friendly alternatives, such as microbial bioherbicides, have been sought. Although these bioherbicides are promising, their efficacy remains a challenge, as evidenced by their limited commercial and industrial production. This article reviews the current status of microbial-based bioherbicides and highlights the potential of cell-free metabolites to improve their efficacy and commercial attractiveness. Stirred tank bioreactors are identified as the most widely used for production-scale submerged fermentation. In addition, the use of alternative carbon and nitrogen sources, such as industrial waste, supports the circular economy. Furthermore, this article discusses the optimization of downstream processes using bioprospecting and in silico technologies to identify target metabolites, which leads to more precise and efficient production strategies. Bacterial bioherbicides, particularly those derived from Pseudomonas and Xanthomonas, and fungal bioherbicides from genera such as Alternaria, Colletotrichum, Trichoderma and Phoma, show significant potential. Nevertheless, limitations such as their restricted range of action, their persistence in the environment, and regulatory issues restrict their commercial availability. The utilization of cell-free microbial metabolites is proposed as a promising solution due to their simpler handling and application. In addition, modern technologies, including encapsulation and integrated management with chemical herbicides, are investigated to enhance the efficacy and sustainability of bioherbicides.

Bioremediation strategies against pesticides: an overview of current knowledge and innovations.

Pesticides pose significant risks to both human health, such as cancer, neurological disorders, and endocrine disruption, and ecosystems, through the destruction of beneficial insects, contamination of soil and water, and impact on non-target species. In the face of escalating pesticide pollution, there is an urgent need for multifaceted approaches to address the issue. Bioremediation emerges as a potent tool in the environmental pollution mitigation arsenal. Ideally aiming for the complete decomposition of pesticides into harmless molecules, bioremediation encompasses diverse approaches - from bioabsorption, bioadsorption, and biotransformation using enzymes and nanoenzymes to comprehensive degradation facilitated by microorganisms such as bacteria, fungi, macro- and microalgae, or phytoremediation. Exploring nature's biodiversity offers a promising avenue to find solutions to this pressing human-induced problem. The acceleration of biodegradation necessitates identifying and developing efficient organisms, achieved through bioprospection and targeted modifications. Specific strategies to enhance process efficiency and throughput include optimizing biomass production, strategic inoculation in diverse environments, and employing bioreactor systems for processing heavily contaminated waters or soils. This comprehensive review presents various bioremediation approaches, emphasizing the importance of microorganisms' exploration and new technologies development, including current innovations and patents to effectively combat pesticide pollution. Furthermore, challenges regarding the effective implementation of these technologies are also addressed.

The Potential of Xylooligosaccharides as Prebiotics and Their Sustainable Production from Agro-Industrial by-Products.

In recent years, concerns about a good-quality diet have increased. Food supplements such as prebiotics have great nutritional and health benefits. Within the diverse range of prebiotics, xylooligosaccharides (XOs) show high potential, presenting exceptional properties for the prevention of systemic disorders. XOs can be found in different natural sources; however, their production is limited. Lignocellulosic biomasses present a high potential as a source of raw material for the production of XOs, making the agro-industrial by-products the perfect candidates for production on an industrial scale. However, these biomasses require the application of physicochemical pretreatments to obtain XOs. Different pretreatment methodologies are discussed in terms of increasing the production of XOs and limiting the coproduction of toxic compounds. The advance in new technologies for XOs production could decrease their real cost (USD 25-50/kg) on an industrial scale and would increase the volume of market transactions in the prebiotic sector (USD 4.5 billion). In this sense, new patents and innovations are being strategically developed to expand the use of XOs as daily prebiotics.