Revalorization of Microalgae Biomass for Synergistic Interaction and Sustainable Applications: Bioplastic Generation

Microalgae and cyanobacteria are photosynthetic microorganisms' sources of renewable biomass that can be used for bioplastic production. These microorganisms have high growth rates, and contrary to other feedstocks, such as land crops, they do not require arable land. In addition, they can be used as feedstock for bioplastic production while not competing with food sources (e.g., corn, wheat, and soy protein). In this study, we review the macromolecules from microalgae and cyanobacteria that can serve for the production of bioplastics, including starch and glycogen, polyhydroxyalkanoates (PHAs), cellulose, polylactic acid (PLA), and triacylglycerols (TAGs). In addition, we focus on the cultivation of microalgae and cyanobacteria for wastewater treatment. This approach would allow reducing nutrient supply for biomass production while treating wastewater. Thus, the combination of wastewater treatment and the production of biomass that can serve as feedstock for bioplastic production is discussed. The comprehensive information provided in this communication would expand the scope of interdisciplinary and translational research.The authors would like to acknowledge the funding provided by Tecnologico de Monterrey through the Bioprocess Research Chair (0020209I13). This work was partially supported by Consejo Nacional de Ciencia y Tecnología (CONACyT), Mexico, under the Sistema Nacional de Investigadores (SNI) program awarded to Hafiz M. N. Iqbal (CVU: 735340) and Roberto Parra-Saldivar (CVU: 35753). The Technology Scholarship to Itzel Y. López-Pacheco (CVU: 859227), Laura Isabel Rodas-Zuluaga (CVU: 943350), and Enrique Hidalgo-Vázquez (CVU: 1095127) by CONACyT is also thankfully acknowledged. Additionally, the authors would like to acknowledge Juan Eduardo Sosa-Hernández for his support. The listed author(s) also want to thank and dedicate this work to “Abraham Molina-Vazquez” who was the great support from conceptualization to compilation of this work. However, much sadly, he is not among us anymore, may his soul rest in peace.Peer reviewe

Environmental persistence, detection, and mitigation of endocrine disrupting contaminants in wastewater treatment plants – a review with a focus on tertiary treatment technologies

Endocrine disrupting chemicals are a group of contaminants that have severe effects on humans and animals when exposed, like cancer and alterations to the nervous and reproductive systems. The increasing concentrations of several endocrine disrupting chemicals in the environment are strongly related to anthropogenic activities, and as the population grows this problem becomes more relevant. Thus, wastewater is one of the main sources of endocrine disrupting chemicals, and the technologies employed during primary and secondary treatment in wastewater treatment plants cannot remove these contaminants. Due to this, researchers have tried to develop more efficient technologies for tertiary treatment of wastewater and reduce the concentration of endocrine disrupting chemicals discharged into the environment. Some of the most promising technologies include adsorption, ultrafiltration, advanced oxidation processes and biodegradation. The use of nanomaterials as adsorbents, catalysts, membranes and supports has played a key role in enhancing the efficiency of these technologies. The results showed that these technologies have great potential on the lab-scale, and even some of them have already been employed at some wastewater treatment plants. However, there are still some challenges to achieving a global implementation of these technologies, related to reducing the costs of materials and enhancing their current performance. The use of biomass/waste derived carbon materials and implementing hybrid technologies are accessible approaches for their implementation in tertiary treatment.This work is part of the project entitled “Contaminantes emergentes y prioritarios en las aguas reutilizadas en agricultura: riesgos y efectos en suelos, producción agrícola y entorno ambiental” funded by CSIC-Tecnológico de Monterrey under the i-Link + program (LINKB20030). The author “Jesús Alfredo Rodríguez-Hernández” acknowledges Consejo Nacional de Ciencia y Tecnología (CONACyT) for awarding a scholarship for a PhD in nanotechnology (CVU: 924193). CONACyT is thankfully acknowledged for partially supporting this work under the Sistema Nacional de Investigadores (SNI) program awarded to Rafael G. Araújo (CVU: 714118), Juan Eduardo Sosa-Hernández (CVU: 375202), Elda M. Melchor-Martínez (CVU: 230784), Manuel Martinez-Ruiz (CVU: 418151), Hafiz M. N. Iqbal (CVU: 735340) and Roberto Parra-Saldívar (CVU: 35753). The authors are also thankful to “Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo” in the Latin American development network “Lacasas Inmovilizadas para la Degradación de Compuestos Aromáticos en Aguas Residuales” (LIDA, project 318RT0552). All listed authors are also grateful to their representative universities/institutes for providing literature facilities and the Biorender online program for the elaboration of the graphical abstract and Fig. 1–5.Peer reviewe

Influence of Low Salt Concentration on Growth Behavior and General Biomass Composition in Lyngbya purpurem (Cyanobacteria)

Cyanobacteria are essential for the vast number of compounds they produce and the possible applications in the pharmaceutical, cosmetical, and food industries. As Lyngbya species’ characterization is limited in the literature, we characterize this cyanobacterium’s growth and biomass. L. purpureum was grown and analyzed under different salinities, culture media, and incubation times to determine the best conditions that favor its cell growth and the general production of proteins, carbohydrates, lipids, and some pigments as phycocyanin and chlorophyll a. In this study, each analyzed biomolecule’s highest content was proteins 431.69 mg g−1, carbohydrates 301.45 mg g−1, lipids 131.5 mg g−1, chlorophyll a 4.09 mg g−1, and phycocyanin 40.4 mg g−1. These results can provide a general context of the possible uses that can be given to biomass and give an opening to investigate possible biocompounds or bio metabolites that can be obtained from it

CO\u3csub\u3e2\u3c/sub\u3e biocapture by \u3ci\u3eScenedesmus\u3c/i\u3e sp. grown in industrial wastewater

Greenhouse gases (GHG) emissions are widely related to climate change, triggering several environmental problems of global concern and producing environmental, social, and economic negative impacts. Therefore, global research seeks to mitigate greenhouse gas emissions. On the other hand, the use of wastes under a circular economy scheme generates subproducts from the range of high to medium-value, representing away to help sustainable development. Therefore, the use of wastewater as a culture medium to grow microalgae strains that biocapture environmental CO2, is a proposal with high potential to reduce the GHG presence in the environment. In this work, Scenedesmus sp. was cultivated using BG-11 medium and industrial wastewater (IWW) as a culture medium with three different CO2 concentrations, 0.03%, 10%, and 20% to determine their CO2 biocapture potential. Furthermore, the concomitant removal of COD, nitrates, and total phosphorus in wastewater was evaluated. Scenedesmus sp. achieves a biomass concentration of 1.9 g L−1 when is grown in BG-11 medium, 0.69 g L−1 when is grown in a combination of BG-11 medium and 25% of industrial wastewater; both cases with 20% CO2 supplied. The maximum CO2 removal efficiency (8.4%, 446±150 mg CO2 L−1 day−1) was obtained with 10% CO2 supplied and using a combination of BG-11 medium and 50% IWW (T2). Also, the highest removal of COD was reached with a combination of BG-11 medium and T2 with a supply of 20% CO2 (82% of COD removal). Besides, the highest nitrates removal was achieved with a combination of BG-11 medium and 75% IWW (T3) with a supply of 10% CO2 (42% of nitrates removal) and the maximum TP removal was performed with the combination of BG-11 medium and 25% IWW (T1) with a supply of 10% CO2 (67% of TP removal). These results indicate that industrial wastewater can be used as a culture media for microalgae growth and CO2 biocapture can be performed as concomitant processes. Highlights • Influence of CO2 on the growth rate of microalgae is investigated. • Influence of CO2 on the growth rate of microalgae cultured in industrial wastewater is investigated. • The carbon fixation ability of Scenedesmus sp. was evaluated in BG-11 and wastewater media. • Microalgae production in wastewater could be an excellent alternative to forced CO2 capture

Anthropogenic contaminants of high concern: Existence in water resources and their adverse effects

Existence of anthropogenic contaminants (ACs) in different environmental matrices is a serious and unresolved concern. For instance, ACs from different sectors, such as industrial, agricultural, and pharmaceutical, are found in water bodies with considerable endocrine disruptors potency and can damage the biotic components of the environment. The continuous ACs exposure can cause cellular toxicity, apoptosis, genotoxicity, and alterations in sex ratios in human beings. Whereas, aquatic organisms show bioaccumulation, trophic chains, and biomagnification of ACs through different entry route. These problems have been found in many countries around the globe, making them a worldwide concern. ACs have been found in different environmental matrices, such as water reservoirs for human consumption, wastewater treatment plants (WWTPs), drinking water treatment plants (DWTPs), groundwaters, surface waters, rivers, and seas, which demonstrate their free movement within the environment in an uncontrolled manner. This work provides a detailed overview of ACs occurrence in water bodies along with their toxicological effect on living organisms. The literature data reported between 2017 and 2018 is compiled following inclusion-exclusion criteria, and the obtained information was mapped as per type and source of ACs. The most important ACs are pharmaceuticals (diclofenac, ibuprofen, naproxen, ofloxacin, acetaminophen, progesterone ranitidine, and testosterone), agricultural products or pesticides (atrazine, carbendazim, fipronil), narcotics and illegal drugs (amphetamines, cocaine, and benzoylecgonine), food industry derivatives (bisphenol A, and caffeine), and personal care products (triclosan, and other related surfactants). Considering this threatening issue, robust detection and removal strategies must be considered in the design of WWTPs and DWTPs. © 2019 Elsevier B.V.The financial support provided by the Bioprocess Research Chair (0020209I13) at Tecnologico de Monterrey, Mexico, Consejo Nacional de Ciencia y Tecnologia (CONACYT), Mexico, and CONACYT-Innovate UK project “Phycopigments” (grant #268792) is thankfully acknowledged. The Master Scholarship awarded by Consejo Nacional de Ciencia y Tecnologia (CONACYT), Mexico to Itzel Y. López-Pacheco (637424) and Arisbe Silva-Núñez (888365) is thankfully acknowledged.Peer reviewe

Combination of nejayote and swine wastewater as a medium for Arthrospira maxima and Chlorella vulgaris production and wastewater treatment

Nejayote and swine wastewater are highly pollutant effluents and a source of organic matter load that sometimes released into water bodies (rivers or lakes), soils or public sewer system, with or without partial treatments. Nejayote is a wastewater product of alkaline cooking of maize, whereas, swine wastewater results from the primary production of pigs for the meat market. Owing to the presence of environmentally related pollutants, both sources are considered the major cause of pollution and thus require urgent action. Herein, we report a synergistic approach to effectively use and/or treat Nejayote and swine wastewater as a cost-effective culture medium for microalgae growth, which ultimately induces the removal of polluting agents. In this study, the strains Arthrospira maxima and Chlorella vulgaris were grown using different dilutions of Nejayote and swine wastewater. Both wastewaters were used as the only source of macronutrients and trace elements for growth. For A. maxima, the treatment of 10% nejayote and 90% of water (T3)resulted in a cell growth of 32 × 10 4 cell/mL at 12 days (μ max = 0.27/d). While, a mixture of 25% swine wastewater, 25% nejayote and 50% water (T2)produced 32 × 10 4 cell/mL at 18 days (μ max = 0.16/d). A significant reduction was also noted as 92% from 138 mg/L of TN, 75% from 77 mg/L of TP, and 96% from 8903 mg/L of COD, among different treatments. For C. vulgaris, the treatment of 10% swine wastewater and 90% water (T1)gave a cell growth of 128 × 10 6 cell/mL (μ max = 0.57/d)followed by T3 yielded 62 × 10 6 cell/mL (μ max = 0.70/d)and T2 yielded 48 × 10 6 cell/mL (μ max = 0.54/d). Up to 91% reduction from 138 mg/L of TN, 85% from 19 mg/L of TP and 96% from 4870 mg/L of COD was also recorded. These results show that microalgae can be used to treat these types of wastewater while at the same time using them as a culture media for microalgae. The resultant biomass can additionally be used for getting other sub-products of commercial interest. © 2019 Elsevier B.V.This work was financially supported by Tecnologico de Monterrey, Bioprocess Research Chair ( 0020209I13 ), CONACYT-Mexican National Council for Research and CONACYT-Innovate UK project Phycopigments (grant #268792 ). The Technology Scholarship to I. Lopez #637424 and A. Silva CVU #888365 by CONACYT is also thankfully acknowledged. The authors also thank Mr. Jose Luis Tamez who kindly provided the swine wastewater used in this study.Peer reviewe

Phycocapture of CO<inf>2</inf> as an option to reduce greenhouse gases in cities: Carbon sinks in urban spaces

Climate change is a shift in the average weather patterns, which could stand for a long-term period. This phenomenon is related to greenhouse gas emissions generated by anthropogenic and non-anthropogenic activities. The most notable climate change effects are the rise of sea levels, changes in the water pH, apparition or increased transmission of diseases, changes in the water cycle, loss of marine ecosystems, and several negative impacts on human health. Due to the adverse effects occasioned by climate change, global initiatives have been taken to mitigate its impact, one of these is the reduction of greenhouse gases such as CO2. Some microorganisms such as photosynthetic bacteria and microalgae can capture CO2 and use it as a carbon source for growth. The outstanding CO2 bio-capture or CO2 phycocapture capacity shown by microalgae make them excellent candidates for reduction of atmospheric CO2 in cities. CO2 phyco-capture equivalent CO2 emissions in Mexico City Metropolitan Area (MCMA) was determined as a case study, considering greenhouse gas emissions in this city. It was estimated that 94,847 tons of microalgae biomass must be produced daily to equal the amount of CO2 emissions (170,726 CO2-eq per day), thus obtaining a zero balance of emissions. For the above, CO2 phyco-capture implementation can be possible in cities and also in open spaces and that even its production can work as the carbon credits nowadays implemented, the space required, and the high capture rate led us to consider that the microalgae production on a larger scale may have a faster effect on the concentration of CO2 globally, which can help with greater urgency to the aims established by 2030.The authors would like to acknowledge the funding provided by Tecnologico de Monterrey through the Bioprocess Research Chair (0020209I13). This work was partially supported by Consejo Nacional de Ciencia y Tecnología (CONACYT) Mexico, under Sistema Nacional de Investigadores (SNI) program awarded to Hafiz M.N. Iqbal (CVU: 735340) and Roberto Parra-Saldivar (CVU: 35753).Peer reviewe

Sources of antibiotics pollutants in the aquatic environment under SARS-CoV-2 pandemic situation

During the last decades, the growth of concern towards different pollutants has been increasing due to population activities in large cities and the great need for food production by the agri-food industry. The effects observed in specific locations have shown the impact over the environment in air, soil and water. Specifically, the current pandemic of COVID-19 has brought into the picture the intensive use of different medical substances to treat the disease and population intensive misuse. In particular, the use of antibiotics has increased during the last 20 years with few regulations regarding their excessive use and the disposal of their residues from different sources. Within this review, an overview of sources of antibiotics to aquatic environments was done along with its impact to the environment and trophic chain, and negative effects of human health due prolonged exposure which endanger the environment, population health, water, and food sustainability. The revision indicates the differences between sources and its potential danger due toxicity, and accumulation that prevents water sustainability in the long run

Antidepressant drugs as emerging contaminants: Occurrence in urban and non-urban waters and analytical methods for their detection

Antidepressants are drugs with a direct action on the brain's biochemistry through their interaction with the neurotransmitters, such as dopamine, norepinephrine, and serotonin. The increasing worldwide contamination from these drugs may be witnessed through their increasing presence in the urban water cycle. Furthermore, their occurrence has been detected in non-urban water, such as rivers and oceans. Some endemic aquatic animals, such as certain fish and mollusks, have bioaccumulated different antidepressant drugs in their tissues. This problem will increase in the years to come because the present COVID-19 pandemic has increased the general worldwide occurrence of depression and anxiety, triggering the consumption of antidepressants and, consequently, their presence in the environment. This work provides information on the occurrence of the most administrated antidepressants in urban waters, wastewater treatment plants, rivers, and oceans. Furthermore, it provides an overview of the analytical approaches currently used to detect each antidepressant presented. Finally, the ecotoxicological effect of antidepressants on several in vivo models are listed. Considering the information provided in this review, there is an urgent need to test the presence of antidepressant members of the MAOI and TCA groups. Furthermore, incorporating new degradation/immobilization technologies in WWTPs will be useful to stop the increasing occurrence of these drugs in the environment.The work is part of the project entitled “Contaminantes emergentes y prioritarios en las aguas reutilizadas en agricultura: riesgos y efectos en suelos, producción agrícola y entorno ambiental” funded by CSIC-Tecnologico de Monterrey under i-Link+ program (LINKB20030). We are also thankful to “Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo” in the Latin American development network “Lacasas Inmovilizadas para la Degradación de Compuestos Aromáticos en Aguas Residuales” (LIDA, project 318RT0552). All listed authors are also grateful to their representative universities/institutes for providing literature facilities.Peer reviewe

Phyco-remediation of swine wastewater as a sustainable model based on circular economy

Pork production has expanded in the world in recent years. This growth has caused a significant increase in waste from this industry, especially of wastewater. Although there has been an increase in wastewater treatment, there is a lack of useful technologies for the treatment of wastewater from the pork industry. Swine farms generate high amounts of organic pollution, with large amounts of nitrogen and phosphorus with final destination into water bodies. Sadly, little attention has been devoted to animal wastes, which are currently treated in simple systems, such as stabilization ponds or just discharged to the environment without previous treatment. This uncontrolled release of swine wastewater is a major cause of eutrophication processes. Among the possible treatments, phyco-remediation seems to be a sustainable and environmentally friendly option of removing compounds from wastewater such as nitrogen, phosphorus, and some metal ions. Several studies have demonstrated the feasibility of treating swine wastewater using different microalgae species. Nevertheless, the practicability of applying this procedure at pilot-scale has not been explored before as an integrated process. This work presents an overview of the technological applications of microalgae for the treatment of wastewater from swine farms and the by-products (pigments, polysaccharides, lipids, proteins) and services of commercial interest (biodiesel, biohydrogen, bioelectricity, biogas) generated during this process. Furthermore, the environmental benefits while applying microalgae technologies are discussed.The authors would like to acknowledge the funding provided by Tecnologico de Monterrey through the Bioprocess Research Chair (0020209I13). I. Lopez acknowledges CONACYT (México) for the support provided in the form of MSc. studies' fellowship no. #888365.Peer reviewe