Utilization Of Microalgae Research Articles

Exploring Exogenous Indole-3-acetic Acid's Effect on the Growth and Biochemical Profiles of Synechocystis sp. PAK13 and Chlorella variabilis.

Microalgae have garnered scientific interest for their potential to produce bioactive compounds. However, the large-scale industrial utilization of microalgae faces challenges related to production costs and achieving optimal growth conditions. Thus, this study aimed to investigate the potential role of exogenous indole-3-acetic acid (IAA) application in improving the growth and production of bioactive metabolites in microalgae. To this end, the study employed different concentrations of exogenously administered IAA ranging from 0.36 µM to 5.69 µM to assess its influence on the growth and biochemical composition of Synechocystis and Chlorella. IAA exposure significantly increased IAA levels in both strains. Consequentially, improved biomass accumulation in parallel with increased total pigment content by approximately eleven-fold in both strains was observed. Furthermore, the application of IAA stimulated the accumulation of primary metabolites. Sugar levels were augmented, providing a carbon source that facilitated amino acid and fatty acid biosynthesis. As a result, amino acid levels were enhanced as well, leading to a 1.55-fold increase in total amino acid content in Synechocystis and a 1.42-fold increase in Chlorella. Total fatty acids content increased by 1.92-fold in Synechocystis and by 2.16-fold in Chlorella. Overall, the study demonstrated the effectiveness of exogenously adding IAA as a strategy for enhancing the accumulation of microalgae biomass and biomolecules. These findings contribute to the advancement of microalgae-based technologies, opening new avenues to produce economically important compounds derived from microalgae.

Microalgal and Nitrogen-Fixing Bacterial Consortia: From Interaction to Biotechnological Potential.

Microalgae are used in various biotechnological processes, such as biofuel production due to their high biomass yields, agriculture as biofertilizers, production of high-value-added products, decontamination of wastewater, or as biological models for carbon sequestration. The number of these biotechnological applications is increasing, and as such, any advances that contribute to reducing costs and increasing economic profitability can have a significant impact. Nitrogen fixing organisms, often called diazotroph, also have great biotechnological potential, mainly in agriculture as an alternative to chemical fertilizers. Microbial consortia typically perform more complex tasks than monocultures and can execute functions that are challenging or even impossible for individual strains or species. Interestingly, microalgae and diazotrophic organisms are capable to embrace different types of symbiotic associations. Certain corals and lichens exhibit this symbiotic relationship in nature, which enhances their fitness. However, this relationship can also be artificially created in laboratory conditions with the objective of enhancing some of the biotechnological processes that each organism carries out independently. As a result, the utilization of microalgae and diazotrophic organisms in consortia is garnering significant interest as a potential alternative for reducing production costs and increasing yields of microalgae biomass, as well as for producing derived products and serving biotechnological purposes. This review makes an effort to examine the associations of microalgae and diazotrophic organisms, with the aim of highlighting the potential of these associations in improving various biotechnological processes.

Enhanced carbon dioxide fixation of Chlorella vulgaris in microalgae reactor loaded with nanofiber membrane carried iron oxide nanoparticles

To improve the CO2 dissolution and carbon fixation in the process of microalgae capturing CO2 from flue gas, a nanofiber membrane containing iron oxide nanoparticles (NPsFe2O3) for CO2 adsorption was prepared, and coupled with microalgae utilization to achieve carbon removal. The performance test results showed that the largest specific surface area and pore size were 8.148 m2 g−1 and 27.505 Å, respectively, when the nanofiber membrane had 4% NPsFe2O3. Through CO2 adsorption experiments, it was found that the nanofiber membrane could prolong the CO2 residence time and increase CO2 dissolution. Then, the nanofiber membrane was used as a CO2 adsorbent and semifixed culture carrier in the Chlorella vulgaris culture process. The results showed that compared with the group without nanofiber membrane (0 layer), the biomass productivity, CO2 fixation efficiency and carbon fixation efficiency of Chlorella vulgaris with 2 layers of membranes increased by 1.4 times.

Microalgae fractionation and pyrolysis of extracted microalgae biopolymers

In order to maximize the economic return from microalgae production, the feasibility of thermochemically converting microalgae by-products which have had one or more biochemical components extracted (lipids and/or protein) needs to be considered. The extracted microalgae are waste stemming from microalgae biorefineries where biodiesel and/or valuable proteins/peptides have been produced. The biorefinery scheme of maximized microalgae utilization based on isolation of lipids or lipids and proteins combined, and the thermochemical conversion of the remaining fractions are discussed in this study. The biopolymer components of Nannochloropsis gaditana were extracted to form a lipid fraction, a protein fraction and a carbohydrate-rich residue. The lipid extraction efficiency reached 76.9 wt.%, however, the efficiency of protein extraction was 42.2 wt.% due to the inability of the extraction process to remove all protein. The surface functional groups and thermochemical characteristics of extracted components were investigated by FTIR and py-GC/MS, respectively. The FTIR results suggested that the extraction process disrupted the microalgae cell walls and released intracellular components. Lipids are recommended to be extracted for biofuel production by transesterification. For specific high protein-containing microalgae, protein extraction has to be considered to obtain high value proteins and derived chemicals. After the extraction of high value products, the carbohydrate-rich residue which is considered of low value, can be used as a fast pyrolysis feedstock instead of the whole microalgae. The pyrolysis chemical pathways as a function of temperature were schematized in order to better understand the reaction mechanisms in microalgae pyrolysis. The formation of alkanes and alkenes at higher temperatures were stemming from the long-chain alcohols and carboxylic acids. The formation pathways of N-heterocyclic compounds include Maillard reactions, cracking of amino acids and the cyclization of amines and amides.

Rheological and physicochemical properties of Spirulina platensis residues-based inks for extrusion 3D food printing

Novel food matrices (such as microalgae, plants, fungi, and microbial proteins) with high protein content and biological value, good amino acid profile, and functionality have been explored. Phycocyanin and active polysaccharides extracted from Spirulina platensis are used as food additives, treatment of colitis, as well as obesity prevention. However, most of the remaining Spirulina platensis residues are mainly used as fish feed at present. 3D food printing is one of the promising development techniques used in the food industry. The aim of this study was to develop a novel 3D printing material of Spirulina platensis residues with shear thinning characteristics, high viscosity and rapid recovery. The effects of moisture content and pretreatment method on the rheological properties of Spirulina platensis residues were clarified. Scanning electron microscopy was used to observe the microstructure and texture profile analysis was used to determine the texture characteristics of Spirulina platensis residues, rheology was used to determine the key 3D printing factors such as viscosity and modulus of Spirulina platensis residues. More importantly, the printing process could be realized under ambient conditions. The development of microalgae residue ink promoted the high-value and comprehensive utilization of microalgae, and also broadened the application of microalgae in the food field.

Application of a membrane photobioreactor combined with microalgae for shrimp culture wastewater treatment

Shrimp farming has emerged as a multi-billion-dollar industry in our country, creating numerous economic benefits. However, this sector has several negative environmental impacts. Recent studies on the utilization of microalgae for wastewater treatment are of current interest due to their environmental remediation ability, as well as their potential to generate economic value from the biomass produced after treatment. This study aimed to evaluate the wastewater treatment efficiency of Chlorella Vulgaris using a PMBR membrane photobiological model in shrimp aquaculture. The evaluation process included an acclimatization phase and a treatment effectiveness evaluation phase, which lasted a total of 101 days. Algae biomass, the removal efficiency of COD, N-NO -, N-NO -, N-NH +, and P-PO 3-, and membrane fouling behavior were analyzed. The initial results demonstrated that the algae were well-adapted to shrimp aquaculture wastewater. The removal efficiency of N-NO -, N-NO -, N-NH +, and P-PO 3- and COD was 88.55%, 76.15%, 84.58%, 78.07%, and 81.33%, respectively. The algae biomass steadily increased from 91.3 mg/L to 327.69 mg/L, reaching an average level of about 208 mg/L. Additionally, the transmembrane pressure (TMP) evaluation indicated that the necessary time for membrane fouling removal was approximately 25-26 days.

Perspective: Multiomics and Machine Learning Help Unleash the Alternative Food Potential of Microalgae.

Food security has become a pressing issue in the modern world. The ever-increasing world population, ongoing COVID-19 pandemic, and political conflicts together with climate change issues make the problem very challenging. Therefore, fundamental changes to the current food system and new sources of alternative food are required. Recently, the exploration of alternative food sources has been supported by numerous governmental and research organizations, as well as by small and large commercial ventures. Microalgae are gaining momentum as an effective source of alternative laboratory-based nutritional proteins as they are easy to grow under variable environmental conditions, with the added advantage of absorbing carbon dioxide. Despite their attractiveness, the utilization of microalgae faces several practical limitations. Here, we discuss both the potential and challenges of microalgae in food sustainability and their possible long-term contribution to the circular economy of converting food waste into feed via modern methods. We also argue that systems biology and artificial intelligence can play a role in overcoming some of the challenges and limitations; through data-guided metabolic flux optimization, and by systematically increasing the growth of the microalgae strains without negative outcomes, such as toxicity. This requires microalgae databases rich in omics data and further developments on its mining and analytics methods.

Utilization of microalgae, Chlorella sp. UMT LF2 for bioremediation of Litopenaeus vannamei culture system and harvesting using bio-flocculant, Aspergillus niger

Microalgae are well known as autotrophic microorganisms in aquaculture wastewater treatment, however their role in the aquaculture system is rarely explored. The purpose of this study is to evaluate the influence of adding microalgae, Chlorella sp. UMT LF2, on the functionality for bioremediation and growth performance of Whiteleg shrimp, Litopenaeus vannamei in the nursery phase reared in a control culture system. Secondly, the response surface methodology (RSM) was used to investigate further on the optimal condition for the harvesting process of excess microalgae biomass using bio-flocculant from the filamentous fungus, Aspergillus niger. The experimental set-up with Chlorella sp. additions were compared to the control group without the microalgae addition based on the water quality, microalgae biomass and shrimp growth performance. Water samples were collected and underwent in-situ and ex-situ involving nine physicochemical parameters. The results showed that introducing microalgae with zero water exchange as treatment tanks reduced the NH3, NO2− and PO43− during the intermediate until the two days before the 30-day culture period's end. Microalgae also enhanced shrimp survival and growth performance significantly 89% as compared to the control, 68%. Furthermore, the culture with the addition of microalgae maintained pH stability and enhanced dissolved oxygen during daytime in the culture water. Therefore, this finding confirmed that Chlorella sp. UMT LF2 addition is promising in improving rearing environment and nursery performance for L. vannamei in culture system. However, further research is required to demonstrate the harvesting by-product from the culture system and the potential applications.

Microalgae-Enabled Wastewater Treatment: A Sustainable Strategy for Bioremediation of Pesticides

Pesticides have been identified as major contaminants of various waterways. Being classified as potential endocrine disrupting compounds, pesticides in aqueous system are highly hazardous to aquatic organisms and the ecosystem. The treatment of pesticide-containing wastewater can be performed through several means, but a wastewater treatment strategy which emphasizes both treatment efficiency and sustainability is a necessity of current time. In this context, bioremediation has been increasingly promoted as an alternative technique for the remediation of diverse pollutants. Particularly, bioremediation which involves the utilization of microalgae for the removal or conversion of pesticides to the harmless or less harmful compounds is becoming a trend. Exploiting microalgae as a tool for wastewater treatment presents multiple advantages over conventional treatment technologies, which include an opportunity to simultaneously treat pesticide-containing wastewater and nutrient recovery for microalgae cultivation as well as less formation of toxic sludge. This review discusses the roles of microalgae in mitigating pesticide pollution issue, while offering an opportunity for nutrient recovery from various wastewater sources. Based on the current laboratory studies, the use of microalgae bioremediation as a promising strategy for pesticide treatment has been rationalized. The establishment of more pilot scale studies is highly encouraged to further facilitate the implementation of this treatment approach for practical application.

Syngas production and gas-N evolution over heterogeneously doped La-Fe-O perovskite-type oxygen carriers in chemical looping gasification of microalgae

Chemical looping gasification (CLG) is a promising technology for syngas production with low pollutant emission. In this study, doped La-Fe-O perovskites including LaFeO3 (LF), LaFe0.5Ni0.5O3 (LN5F5) and La0.3Ba0.7FeO3 (L3B7F) were developed for microalgae CLG. The as-prepared perovskites exhibited an outstanding performance in syngas production with accumulative syngas yield > 33 mol/kg. For gas-N evolution, perovskites were beneficial to the formation of NH3 and HCN, while the iron ore may convert precursors to NO. Below 400 °C, NOx can be stored on the perovskite surface in the form of nitrite/nitrate species. When the temperature was above 700 °C, NOx can be selectively reduced by reducing components in tar or syngas under the catalysis of L3B7F, resulting in the final reduction of NOx emission. Thus, CLG over L3B7F may be a promising way for efficient utilization of microalgae to overcome the intractable nitrogen-related obstacles in the commercial application of biomass gasification technologies.

Coupling phenol bioremediation and biodiesel production by Tetradesmus obliquus: Optimization of phenol removal, biomass productivity and lipid content

There is a growing interest for the utilization of microalgae in the bioremediation of organic pollutants and the use of biomass as a biofuel feedstock. This study investigated the influence of phenol exposure and culture conditions on the phenol removal efficiency, biomass productivity and lipid contents of Tetradesmus obliquus. Plackett-Burman design identified CaCl2, NaNO3, and initial phenol concentration as the most important variables affecting on phenol removal. The optimum conditions to maximize biomass productivity, phenol removal and lipid content were determined using the Box-Behnken experimental design as 150.1 mg L−1 phenol, 0.1 g L−1 NaNO3, and 0.03 g L−1 CaCl2. Under these conditions, phenol was completely removed from the optimized medium after 3 days and the biomass productivity and lipid content were 19.53 mg L−1 day−1 and 27.85% (w/w) after 10 days, respectively. Phenol treatment promoted algal biomass productivity to ∼1.3-folds and lipid productivity to ∼ 1.6-folds higher than the control treatment without adding phenol (negative control). Additionally, phenol altered the fatty acid methyl ester composition and increased the saturated and polyunsaturated fatty acid contents with concomitant decrease in the monounsaturated fatty acids. The predicted biodiesel characteristics viz. iodine value, cetane number, oxidation stability, kinematic viscosity, and flash point, in the presence of phenol were in accordance with the international standards. Accordingly, the present study indicated that phenol could be effectively bioremediated by T. obliquus with simultaneous promotion of the algal biomass and lipid productivity for biofuel production.

Distribution and environmental impact of microalgae production potential under the carbon-neutral target

Microalgae, characterized by high productivity and high oil content, are likely to become the focus of clean renewable energy development. However, there are many studies on the growth characteristics and utilization of microalgae in the existing literature, and there is still a lack of further research on the comprehensive prediction of the potential distribution of microalgae. Therefore, this paper uses the mathematical model of microalgae growth to calculate the annual average yield of potential microalgae in each region of the world according to the global uncultivated land and meteorological data, and then predicts the potential distribution of global microalgae biomass energy. This study evaluated the regions with high potential of microalgal biomass energy in the world, which could provide a reference for the development of microalgal biomass energy and the site selection of microalgal cultivation plants in the future. Meanwhile, the global potential biomass is estimated to be 1.985 × 1011 tonnes, which is equivalent to 7.87 × 1010 tonnes standard coal or 5.51 × 1010 tonnes standard oil. According to the global energy consumption, it is 4.14 times of the global primary energy consumption in 2021. This will not only provide sufficient renewable energy, but also improve the global environment.

From manure to high-value fertilizer: The employment of microalgae as a nutrient carrier for sustainable agriculture

The use of livestock and poultry manures as fertilizers is regarded as an important action in the development of circular agriculture. However, long-term fertilization with manure is accompanied with heavy metals accumulation, pathogens contamination, and ammonia toxicity, which may cause the decline of soil quality and crop productivity. To address the aforementioned problems, in this work, we proposed a “manure-algae-crop” technical route, in which microalgae are employed as a carrier transporting nutrients in manures to soil and crops. This paper presented the advanced techniques which can tackle with the hazardous factors in manures and promote the nutrients assimilation by microalgae. Additionally, the utilization of microalgae in the forms of living cyanobacteria , liquid fertilizer , and slow-release fertilizer was discussed in detail. Particularly, we also focused on the disadvantages of algae fertilizers in different forms. By the end of this work, based on the analysis of current challenges and problems, we discussed the potential solutions and prospects of “manure-algae-crop” technical route. In fact, previous studies have achieved many progresses in algae-based manure remediation and utilization of algae fertilizers. Hence, based on current knowledge, “manure-algae-crop” technical route has greater advantages over traditional models of manures utilization in agriculture. In the foreseeable future, with the development of new technologies, reduction of operational cost, and upgrading of agricultural model, “manure-algae-crop” technical route will be applied more frequently in agriculture. It is expected that this technical route can truly promote the high-value utilization of manures and the development of eco-friendly agriculture. • Manure contains hazardous factors threatening soil quality and crop cultivation. • The “manure-algae-crop” technical route is proposed to utilize manure resource. • Algae serve as a carrier transporting nutrients in manure to soil and crop. • Algae in different forms can be employed for soil quality improvement. • Some challenges must be addressed for the practical application of algae fertilizer.

High-Purity Fucoxanthin Can Be Efficiently Prepared from Isochrysis zhangjiangensis by Ethanol-Based Green Method Coupled with Octadecylsilyl (ODS) Column Chromatography.

The exploitation of new economically valuable microalgae as a sustainable source of minor high-value products can effectively promote the full utilization of microalgae. The efficient preparation of minor products from microalgae remains the challenge, owing to the coexistence of various components with a similar polarity in the microalgae biomass. In this study, a novel approach based on the sustainable-oriented strategy for fucoxanthin (FX) production was proposed, which consisted of four steps, including the culture of microalga, ethanol extraction, ODS column chromatography, and ethanol precipitation. The high-purity FX (around 95%) was efficiently obtained in a total recovery efficiency of 84.28 ± 2.56%. This study reveals that I. zhangjiangensis is a potentially promising feedstock for FX production and firstly provides a potentially eco-friendly method for the scale-up preparation of FX from the microalga I. zhangjiangensis.

Utilization of Nannochloropsis oceanica in plant-based feeds by Atlantic salmon (Salmo salar)

The phototropic microalga Nannochloropsis oceanica is a promising feed ingredient with the potential to provide nutrients including polyunsaturated fatty acids in aquafeeds. Complex and rigid cell walls limit the nutrient utilization of microalgae by Atlantic salmon. Here, we report results from two studies-a laboratory study on post-smolts and a farm trial on consumer-ready fish-that were conducted to understand the efficacy of both treated and untreated whole biomass.In the laboratory study, we investigated if extrusion can be used as a feasible pre-treatment method to enhance digestibility, growth, feed utilization and health of the fish. Here, we employed post smolt Atlantic salmon with an initial average weight of 141.8 ± 28.2 g and they were fed one of the below mentioned experimental feeds in five replicate tanks for 84 days. Four low-fishmeal feeds were formulated; a plant-based control feed without the microalga (CTRL), two feeds containing 7.5 (NE7.5) and 15% (NE15) of the pre-extruded microalga and one feed containing 15% of the un-extruded microalga (NN15). In the farm study, fish of average weight 1.83 ± 0.01 kg were reared in pens for 197 days. In this trial, two experimental feeds were used, a control low-fishmeal feed (CT) and a feed containing 7.5% un-extruded microalga (NW).In the laboratory study, all alga-supplemented feeds lowered weight gain, SGR and TGC compared to the control feed. The FCR and FI did not differ between the CTRL and NE7.5 groups but the parameters were significantly poor in fish fed feeds with the highest incorporation of the alga. Likewise, in the farm study feed conversion was not significantly affected by the inclusion of the microalga. The retention of lipid in the post-smolts showed a linear decrease with the incorporation of the microalga in the feed, and the protein retention was significantly reduced only at the highest incorporation level. The content of sum PUFA and EPA + DHA in fish fed microalgae were numerically and significantly higher in the farm and laboratory studies, respectively. The apparent digestibility coefficient (ADC) of protein and lipid in the post-smolts showed an inverse relation to the incorporation level of the microalga. The digestible lipid and energy retention efficiencies improved (p < 0.05) in fish fed pre-extruded microalgae. Expression of antioxidant and immune genes suggested that the microalga did not impart any negative effects on the post-smolts. The farm study indicated the ability of the alga to plausibly shape the intestinal micromorphology and affect the nutrient absorption as well as peristalsis.Based on the laboratory study, we can state that the differences between the pre-treated and untreated microalga diets were only minor suggesting that inclusion level of the alga in plant-based diets had a more significant effect than the pre-treatment, at least at 15% incorporation level. The main conclusion from both the studies is that Nannochloropsis oceanica in the feeds of Atlantic salmon can facilitate a slight increase in deposition of n-3 fatty acids, EPA and DHA.

Short Communication: Antioxidant activity of ethanol extract of Chlorella sorokiniana cultured in tofu wastewater

Abstract. Mursandi H, Susanty D, Nurhayati L, Okasari AA. 2022. Short Communication: Antioxidant activity of ethanol extract of Chlorella sorokiniana cultured in tofu wastewater. Nusantara Bioscience 14: 155-159. Microalgae are microorganisms that grow quickly and produce secondary metabolites with antioxidant activity. Antioxidants of microalgae can be utilized in various aspects such as cosmetics, pharmaceuticals, supplements, and feed. Microalgae utilization will be more profitable if the microalgae can be cultured on waste media. This study aims to determine the concentration of a suitable medium for the growth of Chlorella sorokiniana Shihira &amp; R.W.Krauss, total flavonoids, total phenolics, and the potential of ethanolic extract of C. sorokiniana as an antioxidant. This study cultured the microalgae C. sorokiniana on tofu liquid waste media at various concentrations (15, 20, 25, and 30%). The growth of C. sorokiniana on the media was observed using a spectrophotometer at 680 nm wavelength. C. sorokiniana biomass was collected on the 7th day. The biomass was extracted using ethanol as a solvent. Phytochemical analysis was performed using the standard method, Total phenolic content, total flavonoid content, and antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) were conducted to determine the IC50 value. The results showed that the best growth of C. sorokiniana was on TLW media at a concentration of 30%. The ethanolic extract of C. sorokiniana showed the presence of alkaloids, flavonoids, steroids, tannins, and saponins. The total phenolic content in the ethanolic extract of C. sorokiniana was 18.39 ± 0.29 mgGAE/g, and the total flavonoid content was 31.93 ± 5,60 mgQE/g. The IC50 of the ethanolic extract of C. sorokiniana was 288.95 mg/L, which shows this extract has a potent antioxidant.

Evolution pathway of nitrogen in hydrothermal liquefaction polygeneration of Spirulina as the typical high-protein microalgae

Hydrothermal liquefaction (HTL) is a promising thermochemical technology for converting microalgae growing in aquatic habitats into fuels as well as high-value chemicals. Microalgae HTL polygeneration was carried out in order to reveal the evolution pathway of nitrogen during the HTL process. In this study, Spirulina with high protein content was subjected to hydrothermal treatment at 200–340 °C. The results show that 65.80–76.34 % of the nitrogen enters into the aqueous phase, while 12.96–34.00 % of the nitrogen is transferred to bio-oil. Ammonium ion is the main nitrogen-containing species in the aqueous phase, and the conversion of nitrogen in Spirulina reaches 11.72–51.18 %. The main nitrogen-containing compounds in bio-oil are cyclodipeptides and fatty acid amides respectively at 200–240 °C and 260–340 °C. Due to incomplete decomposition of Spirulina at 200–240 °C, 0.20–17.12 % of nitrogen is retained in the solid residue in the form of pyrrole-N, protein-N and quaternary-N. Understanding the evolution pathway of nitrogen during microalgae HTL polygeneration is conducive to achieving high-value utilization of microalgae.

Performance of Chlorella sp. and Multicultural Bacteria in Removing Pollutants from Nutrient-Rich Wastewater

The most common method of treating palm oil mill effluent (POME) is by using various types of bacteria communities. However, the utilization of microalgae in consuming the high nutrient content in wastewater offer additional benefit, particularly for CO2 sequestration. In this study, we proposed to evaluate the performance of multicultural bacteria obtained from municipal wastewater and Chlorella sp. for batch treatment of POME at different COD concentrations (ranges between 600 to 1,300 mg/L), microalgae species (C. vulgaris and C. pyrenoidosa) and speed of agitation (0 and 150 rpm). The results showed that between the bacteria and microalgae that are involved in POME treatment, microalgae give high removal of colour (93%) and ammoniacal nitrogen (95%). As for the COD and phosphate removal, both microorganisms show comparable performances. It was observed that C. pyrenoidosa was able to remove more colour compared to C. vulgaris where higher lipid yield production was obtained (47.6%). However, there is no significant impact of agitation on pollutant removal. This study also reveals that co-cultivation of different microalgae species does not affect the efficiency of the system. This study provides an important insight into developing an efficient and environmentally friendly method to treat wastewater by incorporating green technology in the treatment system

Utilization of microalgae [Chlorella vulgaris Beyerinck (Beijerinck)] on plant growth and nutrient uptake of garden cress (Lepidium sativum L.) grown in different fertilizer applications

This study was employed as a pot experiment in the controlled greenhouse conditions in order to investigate the effect of microalgae [Chlorella vulgaris Beyerinck (Beijerinck)] application on plant growth and nutrient uptake of garden cress (Lepidium sativum L.) grown in different doses of mineral fertilizer applications. Sieved soil in 3-liter pots was used as the growing medium. Equal amount of irrigation was applied to all pots during the period from seed sowing to the end of the experiment. Microalgae application was applied twice (100 ml and 150 ml per pot) to the seedling-growing medium. As chemical fertilizer, 0%, 50% and 100% of NPK (160 mg N kg-1, 80 mg P2O5 kg-1, and 100 mg K2O kg-1) were applied. As the parameters in garden cress, shoot height, shoot fresh weight, total soluble content (TSS), chlorophyll amount (SPAD value) and some nutrients element (K, Ca, Fe, Zn, Cu and Mn) contents were examined. At the end of the study, microalgae applications were found to have a promising effect on plant growth and some nutrient uptake. It was observed that the values of the studied traits generally increased in the microalgae application compared to the control group.

Trends on Microalgae-Fungi Consortia Research: An Alternative for Biofuel Production?

The utilization of microalgae and fungi on an industrial scale is a challenge for researchers. Based on the question “how fungi have contributed to microalgae research?,” we verified the scientific trends on microalgae-fungi consortia focused on biofuels production by searching for articles on the Web of Science and Scopus databases through the terms “microalgae*” or phytoplankton and “fung*.” We found 1,452 articles published between 1950 and 2020; since 2006, the publication numbers have increased rapidly. The articles were published in 12 languages, but most were written in English (96.3%). Among 72 countries, China (360 articles), USA (344), and Germany (155) led the publication rank. Among the 10 most-prolific authors, 8 were Chinese, like 5 of the most-productive institutions, whereas the National Cheng Kung University was on the top of the list. The sources that published the most on the subject were: Bioresource Technology (96), PLoS ONE (28), and Science of the Total Environment (26). The keyword analysis emphasized the magnitude of applications in microalgae-fungi consortia research. Confirming this research question, biofuels appeared as a research trend, especially biodiesel, biogas, and related terms like lipid, lipid accumulation, anaerobic digestion, and biogas upgrading. For 70 years, articles have been published, where China and the United States seem to dominate the research scenario, and biodiesel is the main biofuel derived from this consortium. However, microalgae-based biofuel biorefinery is still a bottleneck on an industrial scale. Recent environmental challenges, such as greenhouse gas mitigation, can be a promising field for that microalgae-fungi application.