Cultivation In Wastewater Research Articles

Evaluating bioenergy potential of the Para grass (Brachiaria mutica) biomass produced on a land-free cultivation system while keeping the water-energy-environment nexus sustainable

Producing biomass as a renewable bioenergy feedstock is challenging due to scarcity of agricultural lands. In the present study, a land-free cultivation system was employed to produce the Para grass biomass using industrial and urban wastewaters as growth media. The biomass was pyrolyzed at four different heating rates (10 °C min−1, 20 °C min−1, 30 °C min−1, 40 °C min−1) under an inert environment. The pyrolysis data were analyzed using three isoconversional models namely Flynn-Wall-Ozawa (FWO), Kissenger-Akahira-Sunose (KAS), and Starink. The pyrolysis of both samples occurred in three stages, while major pyrolysis occurred during the second stage (200–400 °C) at the corresponding conversion points (α) ranging from 0.20 to 0.65. The high heating values (HHV) of the biomasses produced on wastewaters were shown to be 18.85 MJKg−1 and 18.14 MJKg−1, respectively. The activation energies ranged from 136.45 to 149.18 kJmol−1, 133.35–146.71 kJmol−1, 133.85–147.23 kJmol−1 estimated through for FWO, KAS, and Starink methods, respectively. Pre-exponential factors showed the first order reaction kinetics and a lower difference (<5 KJmol−1) between the enthalpy change and activation energy (Ea) values indicated the favorable reaction thermodynamics. The pyrolytic gases mainly contained hydrocarbons, aromatics, alcohols, phenols, ketones, aldehydes, carboxylic acids, and esters. Interestingly, the wastewater cultivation improved HHV of the biomasses, lowered the Ea-values, and made the pyrolysis more energy efficient, and this improvement was more obvious for industrial wastewater cultivation. Hence, employing a land-free cultivation system could be a novel and promising approach to produce renewable biomass with improved pyrolysis potential to fuel the future while keeping the energy-water-environment nexus sustainable.

Characterization of a newly isolated cyanobacterium Trichocoleus desertorum BERC08 as a potential feedstock for the algal biorefinery

Cyanobacteria have numerous biotechnological applications in the environment, industry, pharmaceutics, food, feed, and energy which is why future cascading biorefineries are believed to employ cyanobacteria as their feedstock. The present study evaluated the potential of a newly isolated cyanobacterium for its applications in the multiproduct biorefinery. Based on morphology and the gene sequence of 23S rRNA, the strain was identified as Trichocoleus desertorum. Various abiotic growth factors including light, pH, and nutrients were optimized to achieve enhanced biomass production using various wastewaters as low-cost growth media. Accordingly, a 2.24-fold to 6.97-fold higher biomass production (gL-1) and biomass productivity of 0.86 gL-1d-1 with a CO2 fixation rate of 1.576 gL-1d-1 was achieved when cultured in synthetic wastewater. Besides, the impact of wastewater cultivation was studied on the biosynthesis of valuable metabolites including proteins, carbohydrates, lipids, and pigments. Accordingly, the lipid content of the wastewater-cultivated strain was increased from 24 to 30%, and protein content was increased from 27 to 46%. The lipids were trans-esterified to biodiesel which was turned out to be good quality biodiesel, as revealed through GC-MS analysis. Additionally, the wastewater-cultivated strain produced 117.35 mgg-1 (11.73 % of the total dried biomass) of phycobilin in response to nutrient manipulation, where phycocyanin was shown to be the most prominent pigment with a yield of 94.7 mgg-1, which covered 80% of the total pigments. These remarkable features reflected the promising potential of this strain to be employed as a feedstock in the multiproduct biorefinery.

Impact of wastewater cultivation on pollutant removal, biomass production, metabolite biosynthesis, and carbon dioxide fixation of newly isolated cyanobacteria in a multiproduct biorefinery paradigm

The impact of wastewater cultivation was studied on pollutant removal, biomass production, and biosynthesis of high-value metabolites by newly isolated cyanobacteria namely Acaryochloris marina BERC03, Oscillatoria sp. BERC04, and Pleurocapsa sp. BERC06. During cultivation in urabn wastewater, its pH used to adjust from pH 8.0 to 11, offering contamination-free cultivation, and flotation-based easy harvesting. Besides, wastewater cultivation improved biomass production by 1.3-fold when compared to control along with 3.54–4.2 gL-1 of CO2 fixation, concomitantly removing suspended organic matter, total nitrogen, and phosphorus by 100%, 53%, and 88%, respectively. Biomass accumulated 26–36% carbohydrates, 15–28% proteins, 38–43% lipids, and 6.3–9.5% phycobilins, where phycobilin yield was improved by 1.6-fold when compared to control. Lipids extracted from the pigment-free biomass were trans-esterified to biodiesel where pigment extraction showed no negative impact on quality of the biodiesel. These strains demonstrated the potential to become feedstock of an integrated biorefinery using urban wastewater as low-cost growth media.

Constructed wetland for improved wastewater management and increased water use efficiency in resource scarce SAT villages: a case study from Kothapally village, in India

Evaluation a field-scale of constructed wetland (CW) for the treatment of rural wastewater (WW), in resource-scarce semi-arid tropic (SAT) villages, to provide improved wastewater management and increased water use efficiency, was the main objective of this study. A CW was commissioned in Kothapally village of Telangana to treat the wastewater generated from 100 households. The CW was vegetated with Typha latifolia and Canna indica. Average COD, sulfate and inorganic nitrogen removal efficiencies observed were 65%, 60% and 67% respectively, for the study period (one year). Removal efficiency for total coliform was consistently above 80%. The treated wastewater was stored in a farm pond and was utilized for irrigation in the nearby agricultural fields (0.6 ha). This perennial source of water, helped the nearby farmers to cultivate two additional crops, chickpea during rabi and sweetcorn during summer. The assured availability of water reduced their vulnerability to dry spells during the kharif by providing means for lifesaving irrigation. The biomass harvested from the constructed wetland was used as fodder for the livestock. A net additional income of Rs.70,000 (∼US$1,000) was realized by the farmers using the treated wastewater for cultivation. Similar constructed wetland-based wastewater management system can be scaled up across water scarce semi-arid tropics. Novelty statement Field-scale performance evaluation of constructed wetland based wastewater treatment in a semi-arid tropic village is scarce in the literature. The work presented gives a feasibility assessment for this technology critical for its wide-scale application to augment rural wastewater management in resource poor villages.

Resource recovery through bioremediation of wastewaters and waste carbon by microalgae: a circular bioeconomy approach.

Microalgal biomass-based biofuels are a promising alternative to fossil fuels. Microalgal biofuels' major obstacles are the water and carbon sources for their cultivation and biomass harvest from the liquid medium. To date, an economically viable process is not available for algal based biofuels. The circular bioeconomy is an attractive concept for reuse, reduce, and recycle resources. The recovery of nutrients from waste and effluents by microalgae could significantly impact the escalating demands of energy and nutraceutical source to the growing population. Wastewaters from different sources are enriched with nutrients and carbon, and these resources can be recovered and utilized for the circular bioeconomy approach. However, the utilization of wastewaters and waste seems to be an essential strategy for mass cultivation of microalgae to minimizing freshwater consumption, carbon, nutrients cost, nitrogen, phosphorus removal, and other pollutants loads from wastewater and generating sustainable biomass for value addition for either biofuels or other chemicals. Hence, the amalgamation of wastewater treatment with the mass cultivation of microalgae improved the conventional treatment process and environmental impacts. This review provides complete information on the latest progress and developments of microalgae as potential biocatalyst for the remediation of wastewaters and waste carbon to recover resources through biomass with metabolites for various industrial applications and large-scale cultivation in wastewaters, and future perspectives are discussed.

Microalgae cultivation in wastewater for simultaneous nutrients removal and biomass production

This study was based on the comparison for the cultivation of microalgae species Chlorella vulgaris in domestic wastewater and distilled water in order to reduce nutrients and simultaneously generate biomass to produce biodiesel. Microalgae reduces concentration of inorganic pollutants (nutrients), and it was observed that 41% (nitrates) and 37% (orthophosphates) were removed by cultivating microalgae in wastewater, while nitrate and orthophosphate removal efficiency was found to be 36% and 23%, respectively, with its cultivation in distilled water. It is worth mentioning that maximum microalgae biomass productivity was found to be higher at 6.768 mg/L with wastewater cultivation as compared to 3.308 mg/L in distilled water. The lipid extraction from the microalgal biomass produced using wastewater was found to be 25.2% by dry weight. The GC–MS fatty acids analysis of the microalgae lipids demonstrated the presence of myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), oleic acid (C18:1), linoleic (C18:1) and linolenic acids (C18:3), which are favourable to produce biodiesel with better fuel characteristics. FTIR peaks at 1361 cm−1 and another at 1639 cm−1 revealed the presence of ester linkages in microalgae, and a peak at 1000 cm−1 denotes strong polysaccharide (C–O) bonding. Thus, FTIR analysis revealed well-formed microalgae with all characteristic peaks and distinct finger prints of lipid existence. The energy requirement for microalgae cultivation per litre for a 10 day cultivation period showed higher value with distilled water (1.539 kWh) as compared to its cultivation in wastewater (0.966 kWh). Current investigation suggests that microalgae cultivated using domestic wastewater can produce more biomass as compared to its cultivation in distilled water, with a benefit of freshwater conservation. It also treats wastewater by taking up the nutrients and helps in mitigating eutrophication if untreated wastewater is discharged directly into water bodies.

Biological treatment of industrial and domestic wastewater of a brewery in Uzbekistan

During the period of water shortage in the Republic, modern resource-saving irrigation methods and the use of purified and industrial waters and their reuse in irrigation is an urgent problem in ecology. Among the methods for treating industrial wastewater in a cheaper, cost effective way is the biological treatment method. It is the study of the effectiveness of biological treatment of industrial wastewater from primary winemaking using selected strains of aquatic plants (pistia). The object of wastewater research is selecting a Pistia algae strain, carrying out biochemical, hydrochemical analyses of wastewater before and after treatment, and the chemical composition of the Pistia algae biomass. All studies were carried out according to the standard studies of UzGOST for waste and drinking water and algological methods used by the Institute of Botany of ANRUz, State Enterprise "Institute GIDROINGEO", etc. The efficiency of biological purification of wastewaters of primary winemaking by higher aquatic plants of the pistia was established. With the help of the research carried out, the wastewater treatment of the food plant, in particular, the Kibray wine station with the Pistia algae, was established: the optimal parameters of growth, development and purification capacity of pistia algae were established for various variants of experiments and wastewater samples; designed and assembled a semi-industrial plant for biological wastewater treatment of the Kibray wine station and carried out work on industrial wastewater treatment. Wastewater from the Kibray wine station contains organic compounds, namely yeast sediments, proteins, fats, carbohydrates, fiber, which are food for Pistia algae. Pistia biomass obtained after cultivation in wastewater after sterilization can be used as feed in livestock and poultry farming, as it contains a large number of proteins, fats and carbohydrates.

Construction of co-culture of microalgae with microorganisms for enhancing biomass production and wastewater treatment: a review

The development of microalgae cultivation in wastewater has been explored for years. Several wastewaters and nutrient sources related to biomass generation have been combined in recent years. On the other hand, several factors seem to reduce the possibility of industrialized this concept shortly. The growth rate and harvesting cost of the algae are often pointed as the leading cause of the gap for industrialization of this concept. In order to counteract these problems, constructing microalgae in the form of co-culture consortia with microorganisms, such as bacteria and yeast, have been reported to enhance the production of biomass under a short period of cultivation. This review highlights the strategies to combine microbial strains and microalgae for improving the process of biomass generation based on the comparison of the productivity of single and consortium of microalgae cultivation. Subsequently, mechanisms to enhance microalgae growth are scrutinized based on their interaction. Furthermore, critical factors regarding the construction of the consortia are discussed. Eventually, identifying gaps in this concept is displayed to describe the path of future focuses in this potential field.

Utilization of wastewater as nutrient media and biomass valorization in marine Chrysophytes- Chaetoceros and Isochrysis

Abstract Microalgal cultivation in wastewater is a multi-strategic approach for the effective treatment of effluents and sustainable generation of bioenergy as well as byproducts. Rapid growth rate, efficient carbon capturing technique and wide range of tolerance are the key attributes which makes microalgae an outstanding source of renewable energy. The present work involves the comparison of remediation potential of marine diatom Chaetoceros and haptophyte Isochrysis when cultivated on wastewater optimized nutrient media. The results show that both the strains can effectively remediate total nitrite up to 0.63% by T2 of Chaetoceros and 5.57% by T3 of Isochrysis, Remediation of total phosphorous 83–84% by T3 and T4 of Chaetoceros and almost 84–94% by T4 and T5 of Isochrysis. The reduction in chemical oxygen demand was most effective in T3 and T4 of Chaetoceros (146–157 mg L−1) and from T4 to T6 of Isochrysis (89–93%). Further, both the rate of lipid and biomass productivity was recorded highest in T6 of Chaetoceros (0.05 and 2.79 g L−1d−1), and in T4 and T5 of Isochrysis (0.02–0.022 and 1.11–1.27 g L−1d−1), respectively. Concomitantly, triggered productivity of total PUFA from 33.5% to 71.6% in case of Chaetoceros and from 20% to 63.4% in Isochrysis highlights the scope and effectiveness of the optimized nutrient media for cultivation and sustenance of either strain in enumerating their potential as a sustainable feed and source of biofuels.

Microalgae bioremediation: A perspective towards wastewater treatment along with industrial carotenoids production

Carotenoids are natural pigments known for their various health benefits for humans together with various other applications in diverse industries. Considering the high market value of carotenoids in the food and health sector, sustainable production of these metabolites for commercial applications is the need of time. Among various microbial alternatives, microalgae are considered as a rich source of carotenoids along with other metabolites and received special attention. However, commercial microalgae production is not fully developed and diversity of data is available regarding the cost-effectiveness of algal biomass production. Recent studies employing novel technologies and methods, coupled with the utilization of wastewater for algal cultivation are providing an innovative way forward. Implementation of wastewater for the cultivation of microalgae offers an economical, sustainable, and environmentally friendly method of resource utilization and urban wastewater management. This review intends to highlight the potential of microalgae species using wastewater for the production of different categories of carotenoids. The review will discuss the integrated approach that can be implemented for the biosynthesis of these value-added products along with wastewater treatment. Different techniques and factors which can be utilized for the upstreaming and downstreaming of the algal carotenoids will also be addressed in detail along with their challenges. Possible recommendations for the coupling of microalgae with wastewater as an effective method of waste remediation and as a source of potential products are also proposed.

Emerging technologies of algae‐based wastewater remediation for bio‐fertilizer production: a promising pathway to sustainable agriculture

AbstractSoil degradation, overuse of chemical fertilizer, and biodiversity loss are serious problems challenging the sustainable development of modern agriculture. In recent years, owing to the advantages of algae biotechnology in nutrients recovery and soil improvement, the integration of algae‐based wastewater remediation and algal bio‐fertilizer production is emerging into the limelight. In this work, we emphasize on the progresses achieved in the fields of biomass production by algae cultivation in wastewater and application of algal bio‐fertilizers. Particularly, three types of algal bio‐fertilizers, including slow‐release bio‐fertilizer, nitrogen‐fixing cyanobacteria, and liquid bio‐fertilizer, widely evaluated and utilized in agriculture are introduced. To prevent the overly optimistic prediction of algal bio‐fertilizer in a real‐world application, we point out the challenges and technical defects, such as presence of new pollution factors in wastewater, high cost of algal biomass, contamination of algal biomass in wastewater, low productivity of algae and valuable components, high water consumption, and potential threats of cyanobacteria to the environment, that prevent the concept of integrating algae‐based wastewater remediation and algal bio‐fertilizer production from becoming a reality. Based on our knowledge and experience, potential solutions to the aforementioned problems are discussed in depth. It is expected that the emerging technologies of algae‐based wastewater remediation for bio‐fertilizer production will bring human beings into a new era of environmentally‐friendly, high‐yield, and resource‐recycling agriculture. © 2020 Society of Chemical Industry (SCI)

Enhancement of Biomass and Lipid Productivities of Scenedesmus sp. Cultivated in the Wastewater of the Dairy Industry

Microalgae are photoautotrophic microorganisms capable of producing compounds with potential bioenergetic applications as an alternative energy source due to the imminent exhaustion of fossil fuels, their impact on the environment, and the constant population increase. The mass cultivation of these microorganisms requires high concentrations of nutrients, which is not profitable if analytical grade culture media are used. A viable alternative is the use of agro-industrial wastewater, due to the metabolic flexibility of these microorganisms and their ability to take advantage of the nutrients present in these substrates. For the reasons mentioned above, the effect of the cultivation in wastewater from cheese processing on the growth parameters and biomass composition of Scenedesmus sp. was evaluated, and its nutrient removal capacity determined. A high lipid concentration was obtained in the cultures with the dairy effluent (507.81 ± 19.09 mg g−1) compared to the standard culture medium, while the growth parameters remained similar to the control medium. Scenedesmus sp. achieved high percentages of nutrient assimilation of the wastewater used (88.41% and 97.07% for nitrogen and phosphorus, respectively). With the results obtained, the feasibility of cultivating microalgae in agro-industrial wastewater as an alternative culture medium that induces the accumulation of compounds with potential bioenergetic applications was verified.

Remediation of Aquaculture Wastewater Using the Microalga Chlorella sorokiniana

The aquaculture industry requires solutions to several environmental challenges in order to become sustainable, including adequate wastewater management. Aquaculture wastewater (AWW) is rich in nitrogen, phosphorus, organic carbon, and other elements essential for microalgae. Due to the potential for AWW to be used as a microalgal growth medium and the potential of Chlorella sorokiniana to remediate wastewater, the growth of this species in AWW was evaluated. The microalgal growth in AWW was compared to the growth in a modified BG11 growth medium containing similar nutrient concentrations as the AWW. The effect of pH regulation and air-lifting the cell suspension at different airflow rates was also studied. As a result, it was found that C. sorokiniana can grow successfully in AWW; however, its cultivation required pH regulation. This microalga species can reach a biomass concentration of up to 476 mg/L and a biomass productivity of 140 mg/L/day. Furthermore, up to 78% of the nitrogen, 77% of the phosphorus, 70% of the magnesium, 90% of the zinc, and 99% of the nickel contained in the AWW were assimilated by the microalgae. The results of this study show that microalga cultivation in wastewater has great potential to reduce contamination while generating economic benefits.

Microalgae cultivation in wastewater and potential processing strategies using solvent and membrane separation technologies

Microalgae has been utilised in various applications ranging from pharmaceuticals, cosmetics, supplements, liquid fuels as well as food source for human and animals. The upscaling of microalgae production to meet the demand for global consumption has yet to be realized as there are many factors to be considered in the upstream and downstream processing of microalgae biomass. For upstream processing, the high cultivation cost which poses a major setback can be reduced by cultivating the microalgae in wastewater sources, which are widely available and at the same time can lead to bioremediation of these waste sources. The contents of microalgae biomass from wastewater can also be used to produce the desired bioproducts. For downstream processing, the efficiency of traditional processes has long hindered the progression of microalgae to products, hence, the discovery of advanced technologies which can yield higher productivity and good quality products have been studied and upscale to a pilot scale to verify its feasibility. Separation techniques like liquid biphasic system and membrane separation are potential in achieving high yield and separation efficiency to recover valuable products from microalgae and these processes are environmentally friendly and cost-effective. The insights from cultivating microalgae in wastewater sources and the promising technologies to convert them into useful bioproducts will be beneficial to the developments of future upstream and downstream processes.

Biotechnological perspectives to augment the synthesis of valuable biomolecules from microalgae by employing wastewater

Increasing population and urbanization bring along depletion of water resources with notable discharge of industrial and municipal wastewater which is rich in nutrients. Microalgae hold great promise for assimilating the nutrient compounds, particularly the intricate nitrogen (N) and phosphorus (P) compounds from wastewater, resulting in algal biomass enriched with various valuable biomolecules. However, development of strategies involving the cultivation of microalgae for wastewater treatment and production of commodity components is still in its infancy. In this review, the current status of microalgae-mediated wastewater treatment, the existing technological bottlenecks that hamper the effective use of photosynthetic microalgae, and innovative solutions to obviate the shortcomings are discussed. Also, this article highlights the potential use of genetic engineering technologies in overproducing algal biomolecules without impeding cellular biomass accumulation by regulating critical metabolic targets for the development of engineered algal strains. In this context, adaptive laboratory evolution (ALE) could be the promising tool to further empower the engineered strains to mitigate the adverse effect from the wastewater cultivation medium. In summary, this review provides novel insights into the application of genetic engineering strategies for overproducing algal biomass and valuable biomolecules such as lipids and polyunsaturated fatty acids using wastewater in a cost-effective manner.

Prospects for the creation of a waste-free technology for wastewater treatment and utilization of carbon dioxide based on cyanobacteria for biodiesel production

Current fresh water and energy shortage determines the need to study the possibilities of using living objects in bioenergy and environmental purification technologies. The development of waste-free technologies allows waste recycling, which saves raw materials and energy, in turn, reducing waste generation. The effect of different carbon dioxide concentrations and wastewater from households on the growth of cyanobacteria was studied in order to determine their capabilities in the purification processes. It was found that the optimal CO2 concentration for the cultivation of cyanobacteria Cyanobacterium sp. IPPAS B-1200 and Desertifilum sp. IPPAS B-1220 was 10 %, and for the Cyanobacterium aponinum IPPAS B-1201 – 5%. It was revealed that the cultivation of the cyanobacterium Cyanobacterium sp. IPPASB-1200 on wastewater from the water storage reduces the concentration of organic pollutants and, accordingly, improves the physicochemical properties of water. The cleaning percentage for selected pollutants was 68–100 %. It was shown that the most optimal ratio of wastewater to nutrient media for cyanobacteria cultivation were 25:75 and 50:50. The lipid content (%/dry weight) in the biomass of the studied strains of cyanobacteria ranges from 15 to 22% after cultivation in wastewater. It was determined that the strains of Cyanobacterium genus were the most suitable for the production of biodiesel according to their fatty acids composition. It was determined that lipids were composed of only saturated and monounsaturated fatty acids. As a result of the studies, the optimal conditions for the growth of Cyanobacterium sp. IPPAS B-1200 were determined. This microorganism has a good potential to produce biodiesel as a producer of saturated and monounsaturated middle-chain-length fatty acids.

The Effectiveness of the Use of Aquatic Plants (Lemna perpusilla, Landoltia punctata and Azolla pinnata) in the Phytoremediation Process of Catfish Aquaculture Wastewater

Aims: The purpose of this study was to determine aquatic plants (Lemna perpusilla, Landoltila punctata and Azolla pinnata) that have the most effective ability as phytoremediation agents for catfish cultivation wastewater.&#x0D; Study Design: This research was conducted by an experimental method, with a Completely Randomized Design (CRD) consisting of three treatments and four replications.&#x0D; Place and Duration of Study: This research is located at the Wet Laboratory (Ciparanje) of the Faculty of Fisheries and Marine Sciences, Padjadjaran University. Water quality testing is carried out at the Water Resources Laboratory of the Faculty of Fisheries and Marine Sciences. Research was carried out on 20 July-24 September 2019.&#x0D; Methodology: The test wastewater was collected from catfish pond culture and put into twelve aquarium with a volume of 8 litre. Physical and chemical parameters observed include BOD5, dissolved oxygen, CO2 acidity, temperature, nitrate, and phosphate.&#x0D; Results: Lemna perpusilla, Landoltia punctata and Azolla pinnata were able to improve the quality of catfish culture wastewater such as increasing the concentration of dissolved oxygen (DO) and pH, and reducingBOD5, CO2, nitrate and phosphate. Lemna perpusilla was able to reduce the concentration of BOD5, CO2,carbondioxide, nitrate and phosphate from catfish cultivation wastewater by75%; 77.7%; 23.4%; 44.2%, respectively, during the phytoremediation process, and Landoltia punctata was able to reduce the concentrations same parameters by 52%; 68.3%; 17.8%; 18.3% and Azolla pinnata by 41%; 84%; 15.3% and 28.4%.&#x0D; Conclusion: Lemnaper pusillamay improve the quality of catfish culture wastewater better than Landoltia punctata and Azolla pinnata. Lemna perpusilla can be recommended as phytoremediation agents catfish cultivation wastewater to remediate organic matter before being discharged directly into water bodies.

Bioprocessing of cultivated Chlorella pyrenoidosa on poultry excreta leachate to enhance algal biomolecule profile for resource recovery

The aim of this work was to study the cultivation of Chlorella pyrenoidosa on poultry excreta leachate to enhance the biochemical composition of algal biomass. The growth of microalgae was analyzed with different concentrations of poultry excreta leachate in BG-11 and distilled water. The biomolecules observed have high value in the form of carbohydrates (0.64 gL−1), protein (1.02 gL−1), chlorophyll (20 µg mL−1) and lipid amount (0.49 gL−1) with PEL BG -25%. Biomass produced in PEL BG -25% was also found to be 60% (2.5 gL−1) higher than the BG-11 medium as a control (1.5gL−1). Recovery of nutrients was observed with leachate wastewater concentration in terms of nitrate (84.2%), ammonium nitrogen (53.1%), and inorganic phosphate (96.2%). Hence, sustainability of microalgae cultivation in wastewater provides a new insight for resource utilization.

Cyanobacterial polyhydroxybutyrate for sustainable bioplastic production: Critical review and perspectives

PHB is a promising bioplastic material that naturally accumulates in many strains of cyanobacteria. This comprehensive review covers recent advances in several topics including PHB metabolism, material properties, relevant extraction methods and protocols, industrial cultivation strategy, current economic assessment and much more. Ultimately, the profitability of cyanobacterial PHB production is controlled by low PHB productivity as well as expensive cultivation and harvesting equipment. Several research areas for improving viability of cyanobacterial PHB production have also been summarised and perspectives on future efforts suggested including; screening, genetic modification, wastewater cultivation and using chemical modulators among others.

Microalgae harvesting by fungal-assisted bioflocculation

Although the production of biofuels from microalgae has numerous advantages over other raw materials, its large-scale application still comes across economic aspects. In this context, the concept of biorefinery emerges as a strategy to increase the sustainability of this process. Studies have been developed to reduce production costs, especially to optimize the harvesting stage. Among the techniques used, bioflocculation is a promising alternative to traditional harvesting methods, as it is viable in terms of cost, execution and efficiency and, above all, it is a more environmentally appropriate method. This study aimed to perform a bibliometric and systematic review of traditional algal harvesting techniques and the mechanisms governing the different interactions of microorganisms used as bioflocculants, especially fungi. The high efficiencies of microalgae harvesting, combined with the possibility of cultivation in wastewater and the various bioproducts originated from this biomass, show the potential application of bioflocculation in the context of integrated biorefineries.