Waste mitigation and resource recovery from food industry wastewater employing microalgae-bacterial consortium

Synergistic microalgae-duckweed systems for enhanced aquaculture wastewater treatment, biomass recovery, and CO2 sequestration: A novel approach for sustainable resource recovery

Current aquaculture practices generate nutrient-rich effluents that cause significant environmental pollution. This study presents a novel synergistic microalgae-duckweed system integrating Chlorella sp. and Spirodela polyrhiza for sustainable wastewater treatment, biomass valorization, and carbon sequestration. Over a 15-day treatment period, the system achieved unprecedented removal efficiencies: 91.25% for NO3--N, 98.90% for NH4+-N, 100% for total phosphorus, and a 95% reduction in chemical oxygen demand (COD). Concurrently, the system produced 6.67 g/L of microalgal biomass and 90 g/m2 of duckweed biomass significantly higher than those of standalone systems, which showed enhanced protein and lipid contents suitable for bioenergy or feed applications. The dual system sequestered CO2 at a remarkable rate of 1.65 g/L/day, exceeding standalone treatments. Microbial community analysis revealed enriched functional diversity, promoting optimized nutrient cycling and organic matter degradation. Although the system was tested at a lab scale, it demonstrates promising scalability due to its efficient nutrient removal and biomass production, as well as the robustness of the combined microalgae-duckweed treatment approach. This integrated approach not only addresses water pollution but also advances the circular economy by converting aquaculture waste into high-value biomass and mitigating carbon emissions. These findings position the synergistic microalgae-duckweed system as a scalable and eco-friendly solution for sustainable aquaculture management and environmental conservation.

Light-boosted simultaneous acid and salinity gradient energy recovery from wastewater via a nanochannel membrane with multi-objective ion separation ability

The discharge of industrial wastewater has surged to unprecedented levels due to rapid industrialization. Developing effective strategies for the concurrent recovery of resources and energy from wastewater presents a promising pathway toward sustainable development. In this study, a composite nanochannel membrane with light-boosted ion separation capabilities was designed for the concurrent recovery of acid and salinity gradient energy from metallurgical industrial wastewater. The membrane demonstrated remarkable photothermal conversion efficiency, utilizing the synergy between localized surface plasmon resonance of Ti3C2Tx component and molecular vibration of Cu-TCPP component to achieve rapid temperature rise from room temperature to 139.5 °C within 60 s under illumination. This photothermal effect created an effective temperature gradient within nanochannels, enhancing the separation efficiency for both H⁺/Cl⁻ and H⁺/Fe2+ pairs by amplifying the differences in diffusion energy barriers. When applied to acidic wastewater, the membrane achieved an outstanding salinity gradient energy conversion power density of 7.31 W/m2 over an expanded testing area, along with a H+/Fe2+ selectivity of 64.18 for acid recovery. Both energy harvesting and acid recovery performance surpass those of state-of-the-art membranes under identical testing conditions. This work presents a critical strategy for energy conversion and resource recovery from wastewater, contributing to sustainable solutions for energy, environmental, and resource challenges.

Prospective technical and technological insights into microalgae production using aquaculture wastewater effluents

Microalgae biomass is a promising resource addressing climate change and play a role in energy transition for generating biofuels. Due to their ability to produce higher yield per year, biofuels obtained from microalgae are considered 3rd generation-advanced biofuels. The industrial production of microalgae mitigates the effects of CO2 emissions and can be used for wastewater bioremediation since most effluents are rich in nutrients. Using wastewater as growth media for microalgae promotes the principles of circular economy and nutrient recovery. The aquaculture wastewater effluent contains high levels of nitrogenous compounds, as well as phosphates and dissolved organic carbon. The current review aims to identify, centralize, and provide extensive information on the decisive technological and technical factors involved in the growth process of different microalgae species in aquaculture wastewater. The study focuses on technological growth performance indicators, as well as specific control strategies applied to achieve pH control, since it has been highlighted to be one of the most important growth-related cofactors. A bibliometric framework was developed to identify future trends in integrated microalgae production. The scientific literature analysis highlighted the great potential of aquaculture wastewater effluents to be used as growth media for microalgae biomass production, due to superior performance in lipid and carbohydrate productivity. Most control strategies developed for microalgae production systems found in the literature aim at controlling the pH in the bioreactor by injecting CO2, while few other papers consider manipulating the dissolved oxygen. The need for higher-level control arises to not only track pH or DO references but also to maximize the treatment efficiency of the bioreactor.

Reduction of biogenic CO2 emissions, COD and nutrients in municipal wastewater via mixotrophic co-cultivation of Chlorella vulgaris - aerobic-activated sludge consortium

In this study, biogenic CO2 emissions, COD and other nutrients (i.e. TP, TN and N H 4 + - N ) from aerobic treatment in municipal Wastewater Treatment Plants (WWTP) were quantified and reduced by phycoremediation using a mixotrophic co-cultivation of Chlorella vulgaris and activated sludge. It has been shown that the microalgae sludge consortium (A-ASR, R1) outperformed the normal-activated sludge system (ASR, R2). In fact, estimated biogenic CO2 emissions with algae mark 1.20-fold higher removal, COD marks 1.40-fold higher removal, TP marks 1.70-fold higher removal, and N H 4 + - N marks 1.40-fold higher removal, compared to normal activated sludge (ASR, R2). Meanwhile, due to aeration, N O 3 - - N concentration increased in both reactors because some Ns were oxidized through nitrification. Furthermore, COD increased again during C. vulgaris stationary growth; thus, activated sludge addition every 4 days (optimal time) was implemented to maintain algae-bacteria balance. The results suggest that integrating the treatment of GHG emissions and water pollutants in a single, concurrent process can significantly enhance the sustainability and efficiency of wastewater treatment plants, which has not been explored comprehensively. Finally, by leveraging C. vulgaris capabilities for carbon and nutrients sequestration, this study can provide practical guidance for achieving carbon neutrality in a WWTP.

Innovative microalgae technologies for mariculture wastewater treatment: Single and combined microalgae treatment mechanisms, challenges and future prospects

The discharge of aquaculture wastewater, comprising nitrogen, phosphorus, heavy metals, and antibiotics from large-scale aquaculture, poses a significant threat to marine ecosystems and human health. Consequently, addressing the treatment of marine aquaculture wastewater is imperative. Conventional physicochemical treatment methods have various limitations, whereas microalgae-based biological treatment technologies have gained increasing attention in the field of water purification due to their ability to efficiently absorb organic matter from mariculture wastewater and convert CO₂ into biomass products. Microalgae offer potential for highly efficient and cost-effective mariculture wastewater treatment, with particularly noteworthy advancements in the application of combined microalgae technologies. This paper explores the research hotspots in this field through bibliometric analysis and systematically discusses the following aspects: (1) summarizing the current pollution status of mariculture wastewater, including the types and sources of pollutants in various forms of mariculture wastewater, treatment methods, and associated treatment efficiencies; (2) analyzing the factors contributing to the gradual replacement of single microalgae technology with combined microalgae technology, highlighting its synergistic effects, enhanced pollutant removal efficiencies, resource recovery potential, and alignment with sustainable development goals; (3) exploring the mechanisms of pollutant removal by combined microalgae technologies, focusing on their technical advantages in bacterial-algal coupling, immobilized microalgae systems, and microalgal biofilm technologies; (4) discussing the challenges faced by the three main categories of combined microalgae technologies and proposing future improvement strategies to further enhance their application effectiveness. In conclusion, this paper offers a detailed analysis of these emerging technologies, providing a forward-looking perspective on the future development of microalgae-based mariculture wastewater treatment solutions.

Sustainable protein/polysaccharide aerogel for the simultaneous and efficient removal of multiple organic contaminants: Insights from DFT calculations and phenomenological mass-transfer modeling

Wastewater contains various organic contaminants that pose great hazards to human health and the environment. A protein/polysaccharide-derived aerogel, namely, ICMA, was developed as a high-performance adsorbent for the simultaneous and efficient removal of diverse contaminants from wastewater, including melanoidin (MLE), Congo red (CR), and diclofenac (DIC). Metal organic framework (UiO-66-NH2), as a regulatory factor, significantly improved the porosity and pore volume of the ICMA to enhance the capture performance of contaminants. The ICMA exhibited outstanding adsorption efficiency owing to the incorporation of ample polyamine functional groups and its well-developed pore structure, large porosity and pore volume, and remarkable heat resistance. The equilibrium capture capacities of the ICMA were 1364, 2031, and 539 mg/g for MLE, CR, and DIC, respectively, with corresponding removal efficiencies all exceeding 90%. Furthermore, the ICMA can capture cationic dyes through MLE/CR/DIC-bridging interactions. After five cycles, the used ICMA can still maintain a high contaminant removal rate/amount, demonstrating good reusability. The classic adsorption model showed that the capture of contaminants by the ICMA is a double-layered and heterogeneous adsorption orientation. A brand new LWAMTM model demonstrated that the adsorption mass-transfer process is jointly determined by the external mass conveyance, pore diffusion, and adsorption on the active site. Multiple characterizations indicated that the contaminant adsorption onto the ICMA was mainly facilitated by charge interactions, with H-bonds playing a secondary role. Quantum chemical theory simulations further provide insights into the atomic-level mechanisms involved in the capture of contaminants. Hirshfeld surface analysis revealed that the ICMA functions as both an H-bond acceptor and a donor during contaminant adsorption. Scale-up and upgrade adsorption were performed to treat actual/simulated wastewater, establishing the groundwork for the industrial implementation of the ICMA.

Revealing the functional potential of microbial community of activated sludge for treating tuna processing wastewater through metagenomic analysis

Reports regarding the composition and functions of microorganisms in activated sludge from wastewater treatment plants for treating tuna processing wastewater remains scarce, with prevailing studies focusing on municipal and industrial wastewater. This study delves into the efficiency and biological dynamics of activated sludge from tuna processing wastewater, particularly under conditions of high lipid content, for pollutant removal. Through metagenomic analysis, we dissected the structure of microbial community, and its relevant biological functions as well as pathways of nitrogen and lipid metabolism in activated sludge. The findings revealed the presence of 19 phyla, 1,880 genera, and 7,974 species, with Proteobacteria emerging as the predominant phylum. The study assessed the relative abundance of the core microorganisms involved in nitrogen removal, including Thauera sp. MZ1T and Alicycliphilus denitrificans K601, among others. Moreover, the results also suggested that a diverse array of fatty acid-degrading microbes, such as Thauera aminoaromatica and Cupriavidus necator H16, could thrive under lipid-rich conditions. This research can provide some referable information for insights into optimizing the operations of wastewater treatment and identify some potential microbial agents for nitrogen and fatty acid degradation.

A review of emerging membrane-based microalgal-bacterial processes for wastewater treatment: Process configurations, biological and membrane performance, and perspectives

Microalgal-bacterial (MB) consortia create an excellent eco-system for simultaneous COD/BOD and nutrients (N and P) removals in a single step with significant reduction in or complete elimination of aeration and carbonation in the biological wastewater treatment processes. The integration of membrane separation technology with the MB processes has created a new paradigm for research and development. This paper focuses on a comprehensive and critical literature review of recent advances in these emerging processes. Novel membrane process configurations and process conditions affecting the biological performance of these novel systems have been systematically reviewed and discussed. Membrane fouling issues and control of MB biofilm formation and thickness associated with these emerging suspended growth or immobilized biofilm processes are addressed and discussed. The research gaps, challenges, outlooks of these emerging processes are identified and discussed in-depth. The findings from the literature suggest that the membrane-based MB processes are advanced biotechnologies with a significant reduction in energy consumption and process simplification and high process efficiency that are not achievable with current technologies in wastewater treatment. There are endless opportunities for research and development of these novel and emerging membrane-based MB processes.

Establishing an efficient membrane bioreactor for simultaneous pollutant removal and purple bacteria production under salinity stress

Recovering resources from wastewater to alleviate the energy crisis has become the prevailing trend of technological development. Purple phototrophic bacteria (PPB), a group of fast-growing microbes, have been widely noticed for their potential in producing value-added products from waste streams. However, saline contents in these waste streams, such as food processing wastewater pose a big challenge, which not only restrain the pollutant removal efficiency, but also hinder the growth of functional microbes. To overcome this, a photo anaerobic membrane bioreactor cultivating PPB (PPB-MBR) was constructed and its performance upon long-term salinity stress was investigated. PPB-MBR achieved desirable pollutants removal performance with the average COD and NH4+ removal efficiency being 87% (±8%, n = 87) and 89% (±10%, n = 87), respectively during long-term exposure to salinity stress of 1-80 g NaCl L-1. PPB were predominant during the entire operation period of 87 days (60%-80%), obtaining maximum biomass yield of 0.67 g biomass g-1 CODremoved and protein productivity of 0.18 g L-1 d-1 at the salinity level of 20 g NaCl L-1 and 60 g NaCl L-1, respectively. The sum of value-added products in proportion to the biomass reached 58% at maximum at the salinity level of 60 g NaCl L-1 with protein, pigments and trehalose contributing to 44%, 8.7%, and 5%, respectively. Based on economic analysis, the most cost-saving scenario treating food processing wastewater was revealed at salinity level of around 20 g NaCl L-1. However, more optimization tools are needed to boost the production efficiency so that the profit from value-added products can outweigh the additional cost by excess salinity in the future implication.

Enhancing organic matter productivity in microalgal-bacterial biofilm using novel bio-coating

Research on renewable energy from microalgae has led to a growing interest in porous substrate photobioreactors, but their widespread adoption is currently limited to pure microalgal biofilm cultures. The behavior of microalgal-bacterial biofilms immobilized on microporous substrates remains as a research challenge, particularly in uncovering their mutualistic interactions in environment enriched with dissolved organic matter. Therefore, this study established a novel culture platform by introducing microalgal-derived bio-coating that preconditioned hydrophilic polyvinylidene fluoride membranes for the microalgal-bacterial biofilm growth of freshwater microalgae, Chlorella vulgaris ESP 31 and marine microalgae, Cylindrotheca fusiformis with bacteria, Escherichia coli. In the attached co-culture mode, the bio-coating we proposed demonstrated the ability to enhance microalgal growth for both studied species by a range of 2.5 % to 19 % starting from day 10 onwards. Additionally, when compared to co-culture on uncoated membranes, the bio-coating exhibited a significant bacterial growth promotion effect, increasing bacterial growth by at least 2.35 times for the C. vulgaris-E. coli co-culture after an initial adaptation phase. A significant increase of at least 72 % in intracellular biochemical compounds (including chlorophyll, polysaccharides, proteins, and lipids) was observed within just five days, primarily due to the high concentration of pre-coated organic matter, mainly sourced from the internal organic matter (IOM) of C. fusiformis. Higher accumulation of organic compounds in the bio-coating indirectly triggers a competition between microalgae and bacteria which potentially stimulate the production of additional intra-/extra-organic substances as a defensive response. In short, insight gained from this study may represent a paradigm shift in the ways that symbiotic interactions are promoted to increase the yield of specific bio-compounds with the presence of bio-coating.

Resource recovery and valorization of food wastewater for sustainable development: An overview of current approaches

The food processing industry is one of the world's largest consumers of potable water. Agri-food wastewater systems consume about 70% of the world's fresh water and cause at least 80% of deforestation. Food wastewater is characterized by complex composition, a wide range of pollutants, and fluctuating water quality, which can cause huge environmental pollution problems if discharged directly. In recent years, food wastewater has attracted considerable attention as it is considered to have great prospects for resource recovery and reuse due to its rich residues of nutrients and low levels of harmful substances. This review explored and compared the sources and characteristics of different types of food wastewater and methods of wastewater treatment. Particular attention was paid to the different methods of resource recovery and reuse of food wastewater. The diversity of raw materials in the food industry leads to different compositional characteristics of wastewater, which determine the choice and efficiency of wastewater treatment methods. Physicochemical methods, and biological methods alone or in combination have been used for the efficient treatment of food wastewater. Current approaches for recycling and reuse of food wastewater include culture substrates, agricultural irrigation, and bio-organic fertilizers, recovery of high-value products such as proteins, lipids, biopolymers, and bioenergy to alleviate the energy crisis. Food wastewater is a promising substrate for resource recovery and reuse, and its valorization meets the current international policy requirements regarding food waste and environment protection, follows the development trend of the food industry, and is also conducive to energy conservation, emission reduction, and economic development. However, more innovative biotechnologies are necessary to advance the effectiveness of food wastewater treatment and the extent of resource recovery and valorization.

Process for nutrient recycling from intensive aquaculture through microalgae-bacteria consortium

This work studies a biological process based on a microalgae-bacteria consortium for recycling nutrients in a recirculating aquaculture system (RAS) implanted in an intensive marine aquaculture farm. Additionally, some techniques were used for microalgae biomass harvesting and tested the effectiveness of filtration by a column with multi-layer sand to reduce the solids concentrations in the effluent. The consortium was grown in photobioreactors in batch and semi-continuous operation modes using the solids concentrated stream generated in the RAS system. The semi-continuous operation showed a high percentage of TDN and TDP removal, achieving final concentrations of 1.09 ± 0.02 mg·L-1 and 0.01 ± 0.01 mg·L-1, respectively, while DOC was reduced to 3.87 ± 0.06 mg·L-1. The values of productivity 44 ± 9 mg TSS·L-1 indicated that the studied stream is a suitable culture medium for the growth of the microalgae-bacteria consortium. A combination of harvesting techniques was studied, coagulation-flocculation-settling and coagulation-flocculation-flotation. The first step was to optimise the dose of FeCl3 through the coagulation-flocculation test to pre-concentrate the biomass generated, achieving an optimal dose of 0.106 mg Fe·mg TSS-1. Then, two separation processes were applied to the stream and compared: settling and flotation. The maximum removal efficiency (90.2 ± 0.3 %) was obtained in the settling process, so the coagulation-flocculation-settling was select as the best combination of harvesting techniques. Finally, sand filtration was studied as an effluent refining process to improve solids reduction of the water obtained in the harvesting step resulting in an effluent with 17.18 ± 1.49 mg TSS·L-1. The proposed sequence process is capable of recycling nutrients from an intensive marine aquaculture farm by using these resources via transformation into microalgae biomass and generating quality effluent.

Microalgae-assisted green bioremediation of food-processing wastewater: A sustainable approach toward a circular economy concept

Wastewater disposal is a major environmental issue that pollutes water, causing eutrophication, habitat destruction, and economic impact. In Mexico, food-processing effluents pose a huge environmental threat due to their excessive nutrient content and their large volume discharged every year. Some of the most harmful residues are tequila vinasses, nejayote, and cheese whey. Each liter of tequila generates 13-15 L of vinasses, each kilogram of cheese produces approximately 9 kg of cheese whey, and each kilogram of nixtamalized maize results in the production of 2.5-3.3 L of nejayote. A promising strategy to reduce the contamination derived from wastewater is through microalgae-based wastewater treatment. Microalgae have a high adaptability to hostile environments and they can feed on the nutrients in the effluents to grow. Moreover, to increase the viability, profitability, and value of wastewater treatments, a microalgae biorefinery could be proposed. This review will focus on the circular bioeconomy scheme focused on the simultaneous food-processing wastewater treatment and its use to grow microalgae biomass to produce added-value compounds. This strategy allows for the revalorization of wastewater, decreases contamination of water sources, and produces valuable compounds that promote human health such as phycobiliproteins, carotenoids, omega-3 fatty acids, exopolysaccharides, mycosporine-like amino acids, and as a source of clean energy: biodiesel, biogas, and bioethanol.

Continuous cultivation of mixed-culture microalgae using anaerobic digestion effluent in photobioreactors with different strategies for adjusting nitrogen loading rate

This study examined continuous mixed-culture microalgae cultivation for nutrient removal from anaerobic digestion (AD) effluents in photobioreactors, while altering the NH4+-N loading rate (NLR) by adjusting either the hydraulic retention time (HRT) (reactor set RH) or the influent NH4+-N concentration (reactor set RS). Both RH and RS demonstrated efficient nutrient removal and microalgae cultivation at NLRs of 4-10 mg NH4+-N/L∙d, reaching peak performance at 10 mg NH4+-N/L∙d. Within this range, RH obtained greater biomass yield and productivity, while RS maintained higher microalgal concentrations. The cultivated biomasses obtained from RH and RS had good settleability and suitable fatty acid compositions as a biodiesel feedstock, although their organic composition varied considerably with NLR and HRT. Parachlorella overwhelmingly dominated the reactors' microalgal communities throughout the experiment, co-existing with various microalgae-associated bacteria. Changes in NLR significantly influenced the bacterial community structures, underscoring its critical role in determining reactor performance and microalgal-bacterial community behavior.

Highly Efficient Cd2+ Removal Using Tobermorite with pH Self-Adjustment Ability from Aqueous Solution

Cadmium (Cd), as a type of heavy metal, can increase the incidence of many diseases, even in low concentrations. In this study, tobermorite was hydrothermally synthesized and then applied to adsorb Cd²⁺ from an aqueous solution. The physicochemical characteristics of the synthesized tobermorite were detected, and the results indicated that the well-crystallized tobermorite had a lot of mesopores and a large specific surface area of 140.92 m²/g. It acquired a pH self-adjustment ability via spontaneously releasing Ca²⁺ and OH^- into the aqueous solution. The effects of different factors on Cd²⁺ removal were investigated. For Cd²⁺, the removal efficiency could reach 99.71% and the maximum adsorption capacity was 39.18 mg/g using tobermorite. The adsorption data was best fitted with the pseudo-second-order kinetic and Langmuir isotherm models. In addition, there was no strict limit on the solution pH in Cd²⁺ adsorption because the tobermorite could adjust the solution pH to an alkaline atmosphere spontaneously. The efficient removal of Cd²⁺ using tobermorite was a result of surface complexation and ion exchange.

Strategies for enhancing the efficacy of anaerobic digestion of food industry wastewater: An insight into bioreactor types, challenges, and future scope

Food waste have become a growing concern worldwide with raising population and economic growth. Wastewater discharged from food industries contains many valuable and toxic components that have a negative impact on the ecological system. Large amounts of wastewater are discharged from the food industry, which necessitates the creation of effective technologies. Wastewater from the food industry can be seen as a rich source of energy and a primary source for generating valuable products. Waste disposal and resource recovery are sustainably valued by anaerobic digestion of wastewater from the food sector. The characteristics, composition, and nature of wastewater produced from various food sectors are elaborated upon in this review. An overview of the anaerobic digestion process for wastewater treatment in the food industry is included. Enhancement strategies for the anaerobic digestion process have been discussed in detail. In addition, various types of reactors utilized for performing anaerobic digestion is illustrated. Though anaerobic digestion process possesses advantages, the challenges and future scope are examined for improving the outcome.

Valorization of wastewater: A paradigm shift towards circular bioeconomy and sustainability

Limitation in the availability of natural resources like water is the main drive for focussing on resource recovery from wastewater. Rapid urbanization with increased consumption of natural resources has severely affected its management and security. The application of biotechnological processes offers a feasible approach to concentrating and transforming wastewater for resource recovery and a step towards a circular economy. Wastewater generally contains high organic materials, nutrients, metals and chemicals, which have economic value. Hence, its management can be a valuable resource through the implementation of a paradigm transformation for value-added product recovery. This review focuses on the circular economy of "close loop" process by wastewater reuse and energy recovery identifying the emerging technologies for recovering resources across the wastewater treatment phase. Conventional wastewater treatment technologies have been discussed along with the advanced treatment technologies such as algal treatment, anammox technology, microbial fuel cells (MFC). Apart from recovering energy in the form of biogas and biohydrogen, second and third-generation biofuels as well as biohythane and electricity generation have been deliberated. Other options for resource recovery are single-cell protein (SCP), biopolymers as well as recovery of metals and nutrients. The paper also highlights the applications of treated wastewater in agriculture, aquaponics, fisheries and algal cultivation. The concept of Partitions-release-recover (PRR) has been discussed for a better understanding of the filtration treatment coupled with anaerobic digestion. The review provides a critical evaluation on the importance of adopting a circular economy and their role in achieving sustainable development goals (SDGs). Thus, it is imperative that such initiatives towards resource recovery from wastewater through integration of concepts can aid in providing wastewater treatment system with resource efficiency.

Understanding the influence of free nitrous acid on microalgal-bacterial consortium in wastewater treatment: A critical review

Microalgal-bacterial consortium (MBC) constitutes a sustainable and efficient alternative to the conventional activated sludge process for wastewater treatment (WWT). Recently, integrating the MBC process with nitritation (i.e., shortcut MBC) has been proposed to achieve added benefits of reduced carbon and aeration requirements. In the shortcut MBC system, nitrite or free nitrous acid (FNA) accumulation exerts antimicrobial influences that disrupt the stable process performance. In this review, the formation and interactions that influence the performance of the MBC were firstly summarized. Then the influence of FNA on microalgal and bacterial monocultures and related mechanisms together with the knowledge gaps of FNA influence on the shortcut MBC were highlighted. Other challenges and future perspectives that impact the scale-up of the shortcut MBC for WWT were illustrated. A potential roadmap is proposed on how to maximize the stable operation of the shortcut MBC system for sustainable WWT and high-value biomass production.

Sustainable utilization of unavoidable food waste into nutritional media for the isolation of bacterial culture for the removal of heavy metals

This study aims to reuse food waste (FW) as growth media for bacterial cultures for bioremediation of heavy metal. The best natural medium was selected based on the carbon, nitrogen, and other elements. The batch culture of Comamonas terrae showed growth stability for 16 days in the pig bone medium. C. terrae showed the best growth at pH of 7.4, temperature of 35 °C, and medium concentration of 10 g/L. The C. terrae showed heavy metal (HM) removal efficiencies of Cd (52 %) Cr (63 %) Pb (62 %) and Zn (55 %). In addition, the Fourier transform infrared spectroscopy results revealed the bioadsorption of HM in C. terrae. The study suggests the C. terrae can efficiently remove HM and C. terrae may be used for bioremediation of HM. Therefore, pig bone waste is a cost-effective medium and a good solution for the valorization and reuse of FW in line with the circular economy.

A review on biodiesel production from microalgae: Influencing parameters and recent advanced technologies

Microalgae are the important part of carbon cycle in the nature, and they could utilize the carbon resource in water and soil efficiently. The abilities of microalgae to mitigate CO₂ emission and produce oil with a high productivity have been proven. Hence, this third-generation biodiesel should be popularized. This review firstly introduce the basic characteristics and application fields of microalgae. Then, the influencing parameters and recent advanced technologies for the microalgae biodiesel production have been discussed. In influencing parameters for biodiesel production section, the factors of microalgae cultivation, lipid accumulation, microalgae harvesting, and lipid extraction have been summarized. In recent advanced technologies for biodiesel production section, the microalgae cultivation systems, lipid induction technologies, microalgae harvesting technologies, and lipid extraction technologies have been reviewed. This review aims to provide useful information to help future development of efficient and commercially viable technology for microalgae-based biodiesel production.