A promising approach to enhance microalgae productivity by exogenous supply of vitamins

Biomass and hydrocarbon production from Botryococcus braunii: A review focusing on cultivation methods

Botryococcus braunii has garnered significant attention in recent years due to its ability to produce high amounts of renewable hydrocarbons through photosynthesis. As the world shifts towards a greener future and seeks alternative sources of energy, the cultivation of B. braunii and the extraction of its hydrocarbons can potentially provide a viable solution. However, the development of a sustainable and cost-effective process for cultivating B. braunii is not without challenges. Compared to other microalgae, B. braunii grows very slowly, making it time-consuming and expensive to produce biomass. In response to these challenges, several efforts have been put into optimizing Botryococcus braunii cultivation systems to increase biomass growth and hydrocarbon production efficiency. This review presents a comparative analysis of different Botryococcus braunii cultivation systems, and the factors affecting the productivity of biomass and hydrocarbon in Botryococcus braunii are critically discussed. Attached microalgal growth offers several advantages that hold significant potential for enhancing the economic viability of microalgal fuels. Here, we propose that employing attached growth cultivation, coupled with the milking technique for hydrocarbon extraction, represents an efficient approach for generating renewable fuels from B. braunii. Nevertheless, further research is needed to ascertain the viability of large-scale implementation.

Selecting for a high lipid accumulating microalgae culture by dual growth limitation in a continuous bioreactor

A dual-growth-limited continuous operated bioreactor (chemostat) was used to enhance lipid accumulation in an enrichment culture of microalgae. The light intensity and nitrogen concentration where both limiting factors resulting in high lipid accumulation in the mixed culture. Both conditions of light and nitrogen excess and deficiency were tested. Strategies to selectively enrich for a phototrophic lipid-storing community, based on the use of different nitrogen sources (ammonium vs. nitrate) and vitamin B supplementation in the growth medium, were evaluated. The dual limitation of both nitrogen and light enhanced the accumulation of storage compounds. Ammoniacal nitrogen was the preferred nitrogen source. Vitamin B supplementation led to a doubling of the lipid productivity. The availability of vitamins played a key role in selecting an efficient lipid-storing community, primarily consisting of Trebouxiophyceae (with an 82 % relative abundance among eukaryotic microorganisms). The obtained lipid volumetric productivity (387 mg L-1 d-1) was among the highest reported in literature for microalgae bioreactors. Lipid production by the microalgae enrichment surpassed the efficiencies reported for continuous microalgae pure cultures, highlighting the benefits of mixed-culture photo-biotechnologies for fuels and food ingredients in the circular economy.

Dynamic metabolomic crosstalk between Chlorella saccharophila and its new symbiotic bacteria enhances lutein production in microalga without compromising its biomass

The microalgae Chlorella saccharophila UTEX247 was co-cultured with its symbiotic indigenous isolated bacterial strain, Exiguobacterium sp., to determine the possible effects of bacteria on microalgae growth and lutein productivity. Under optimal conditions, the lutein productivity of co-culture was 298.97 µg L-1 d-1, which was nearly 1.45-fold higher compared to monocultures i.e., 103.3 µg L-1 d-1. The highest lutein productivities were obtained in co-cultures, accompanied by a significant increase in cell biomass up to 0.84-fold. These conditions were analyzed using an untargeted metabolomics approach to identify metabolites enhancing valuable renewables, i.e., lutein, without compromising growth. Our qualitative metabolomic analysis identified nearly 30 (microalgae alone), 41 (bacteria alone), and 75 (co-cultures) metabolites, respectively. Among these, 46 metabolites were unique in the co-culture alone. The co-culture interactions significantly altered the role of metabolites such as thiamine precursors, reactive sugar anomers like furanose and branched-chain amino acids (BCAA). Nevertheless, the central metabolism cycle upregulation depicted increased availability of carbon skeletons, leading to increased cell biomass and pigments. In conclusion, the co-cultures induce the production of relevant metabolites which regulate growth and lutein simultaneously in C. saccharophila UTEX247, which paves the way for a new perspective in microalgal biorefineries.

Multi response surface optimization, Pareto analysis and kinetics study of microalgal post-treatment systems

High concentrations of nutrients are observed in the effluent of different wastewater treatment plants, while additional costs of post-treatment systems and low-value sludge are the main reasons for releasing such effluents. The present study aims to introduce an increased procedure for simultaneous nutrient recovery and biomass production using an algae-based post-treatment technique. The procedure has been utilized by two well-known strains (Scenedesmus dimorphus and Chlorella vulgaris) cultivated in different N/P ratios (16, 62, and 108) and trace metals (0, 50%, and 100%) in a synthetic meat processing wastewater as a model to investigate effects of the factors on microalgal cultivation and nutrient removal. Pareto statistical analysis and Multi Response Surface methodology were applied to determine the priority of factors and their optimum values, respectively. The unbalanced N/P ratio and lack of trace metals were introduced as two main reasons for the significant decrease of about 60% and 120% in nutrient removal and biomass production. The optimized procedure resulted in significant increases in the removal efficiencies where 90%, 83%, and 65% were achieved for ammonium, nitrate, and phosphate, respectively. Moreover, a 72% increase in biomass production was reported in the optimal points. The results of the Pareto analysis highlighted the significant superiority (about two times) of the trace metals in removal efficiencies. Finally, experimental data has also been modelled by Verhulst logistic model that successfully described the microalgae growth. This procedure showed promising results of microalgal systems to supersede the conventional post-treatment systems.

Protein Quality and Protein Digestibility of Vegetable Creams Reformulated with Microalgae Inclusion

Microalgae are considered a valuable source of proteins that are used to enhance the nutritional value of foods. In this study, a standard vegetable cream recipe was reformulated through the addition of single-cell ingredients from Arthrospira platensis (spirulina), Chlorella vulgaris, Tetraselmis chui, or Nannochloropsis oceanica at two levels of addition (1.5% and 3.0%). The impact of microalgae species and an addition level on the amino acid profile and protein in vitro digestibility of the vegetable creams was investigated. The addition of microalgae to vegetable creams improved the protein content and the amino acid nutritional profile of vegetable creams, whereas no significant differences were observed in protein digestibility, regardless of the species and level of addition, indicating a similar degree of protein digestibility in microalgae species despite differences in their protein content and amino acid profile. This study indicates that the incorporation of microalgae is a feasible strategy to increase the protein content and nutritional quality of foods.

Development of Microalgae Biodiesel: Current Status and Perspectives

Microalgae are regarded as a promising source of biodiesel. In contrast with conventional crops currently used to produce commercial biodiesel, microalgae can be cultivated on non-arable land, besides having a higher growth rate and productivity. However, microalgal biodiesel is not yet regarded as economically competitive, compared to fossil fuels and crop-based biodiesel; therefore, it is not commercially produced. This review provides an overall perspective on technologies with the potential to increase efficiency and reduce the general costs of biodiesel production from microalgae. Opportunities and challenges for large-scale production are discussed. We present the current scenario of Brazilian research in the field and show a successful case in the research and development of microalgal biodiesel in open ponds by Petrobras. This publicly held Brazilian corporation has been investing in research in this sector for over a decade.

Heterotrophic Cultivation of Euglena gracilis in Stirred Tank Bioreactor: A Promising Bioprocess for Sustainable Paramylon Production

Paramylon is a valuable intracellular product of the microalgae Euglena gracilis, and it can accumulate in Euglena cells according to the cultivation conditions. For the sustainable production of paramylon and appropriate cell growth, different bioreactor processes and industrial byproducts can be considered as substrates. In this study, a complex medium with corn steep solid (CSS) was used, and various bioreactor processes (batch, fed batch, semicontinuous and continuous) were performed in order to maximize paramylon production in the microalgae Euglena gracilis. Compared to the batch, fed batch and repeated batch bioprocesses, during the continuous bioprocess in a stirred tank bioreactor (STR) with a complex medium containing 20 g/L of glucose and 25 g/L of CSS, E. gracilis accumulated a competitive paramylon content (67.0%), and the highest paramylon productivity of 0.189 g/Lh was observed. This demonstrated that the application of a continuous bioprocess, with corn steep solid as an industrial byproduct, can be a successful strategy for efficient and economical paramylon production.

Cross-feeding among microalgae facilitates nitrogen recovery at low C/N

Although co-culture of microalgae has been found as a feasible strategy to improve biomass production, their interspecies relationships are not fully understood. Here, two algae taxa, Chlorella sp. and Phormidium sp., were mono-cultured and co-cultured in three photobioreactors for 70 days with periodically harvesting to investigate how dual-species interaction influence nitrogen recovery. Results showed that the co-culture system achieved a significantly higher protein production and nitrogen removal rate than those in the individual cultures at a C/N ratio of 3:1 (p < 0.05). Genome-Centered metagenomic analysis revealed their cooperative relationship exemplified by cross-feeding. Phormidium sp. had the ability to synthesize pseudo-cobalamin, and Chlorella sp. harbored the gene for remodeling the pseudo-cobalamin to bioavailable vitamin B12. Meanwhile, Chlorella sp. could contribute the costly amino acid and cofactors for Phormidium sp. Their symbiotic interaction facilitated extracellular polymeric substances (EPS) production and nitrogen recovery. The EPS concentration in co-culture was positively related to the settling efficiency (R² = 0.774), which plays an essential role in nitrogen recovery. This study provides new insights into microbial interactions among the photoautotrophic community and emphasizes the importance of algal interspecies interaction in algae-based wastewater treatment.

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

Wastewater generated by the food industry is rich in nitrogen and phosphorus with possible presence of heavy metals. Physical and chemical methods of treatment, although effective, are expensive and may cause secondary environmental pollution damaging aquatic and human life. Traditional biological methods are eco-friendly and cost-effective but involve standalone microorganisms that pose risk of contamination and are not as effective. This review discusses the application of novel microalgal-bacterial consortium as a solution for the resource recovery and treatment of dairy, starch and aquaculture wastewater. Use of biofilm reactors containing anaerobic and aerobic sludge has shown 80-90% and > 90% COD and nutrient removal efficiency in treatment of dairy and starch processing wastewater, respectively. The treatment of aquaculture processing wastewater can be challenging due to high sality and requires salt-tolerant bacteria-microalgae consortium. In this regard, the identification of dominant microalgae and bacteria using 16S rRNA and 18S rRNA genes is recommended.

Assessment of Antioxidant and Anticancer Activities of Microgreen Alga Chlorella vulgaris and Its Blend with Different Vitamins

There is a very vital antioxidant extracted from microgreen alga. Chlorella vulgaris has major advantages and requires high yield worldwide. Some microalgae require vitamins for their growth promotion. This study was held to determine the impact of different vitamins including Thiamine (B1), Riboflavin (B2), Pyridoxine (B6), and Ascorbic acid (c) at concentrations of 0.02, 0.04, 0.06, and 0.08 mg/L of each. Each vitamin was added to the BG11 growth medium to determine the effect on growth, total carbohydrate, total protein, pigments content, antioxidant activities of Chlorella vulgaris. Moreover, antitumor effects of methanol extract of C. vulgaris without and with the supplement of thiamine against Human prostate cancer (PC-3), Hepatocellular carcinoma (HEPG-2), Colorectal carcinoma (HCT-116) and Epitheliod Carcinoma (Hela) was estimated in vitro. C. vulgaris supplemented with various vitamins showed a significant increase in biomass, pigment content, total protein, and total carbohydrates in comparison to the control. Thiamine was the best vitamin influencing as an antioxidant. C. vulgaris supplemented with thiamine had high antitumor effects in vitro. So, it’s necessary to add vitamins to BG11 media for enhancement of the growth and metabolites.

Enhanced biomass production of Synechocystis sp. PCC 6803 by two associated bacteria Paenibacillus camelliae and Curtobacterium ammoniigenes

Synechocystis sp. PCC 6803 grown continuously in a 5-L photo-bioreactor for 20 months was found to have associated consortia with heterotrophic microorganisms. Two strains of bacteria were isolated from the long-term cultures of cyanobacteria with the aim to test whether their presence affects cyanobacterial growth and metabolism. The two strains were phylogenetically identified as Paenibacillus camelliae and Curtobacterium ammoniigenes, respectively. Co-culturing the Synechocystis sp. with either of the isolates under photoautotrophic and photoheterotrophic conditions exerted a statistically significant growth enhancement effect on cyanobacteria. Under co-culture experiments, the addition of P. camelliae resulted in a four-fold higher biomass yield with a considerable decrease in the stationary period. The growth was more pronounced on the addition of acetate to the culture media. Growth-enhancing factors like indole acetic acid (IAA) and siderophores were detected in the co-culture conditions which proved to be the main driving force in boosting cyanobacterial growth. Thus, the cyanobacteria-bacteria consortia can be very useful for augmenting biomass production by circumventing the time factor which can be further exploited for various biotechnological applications.

Molasses as a new nutrition medium for Scenedsmus quadricauda growth and production of some bio compounds

Algae comprise a large group of Thallophyta, which may be used as direct nutrition of human beings. Molasses is the by-product of the sugar manufacturing facility. In this study, a locally isolated Scendsmus quadricauda from the environment of Mosul in the Shalalat region was obtained. Biomass of Scenedsmus was measurement by carried out and filtration then drying in an oven for 24 h and weighed, Estimation of chlorophyll and protein and carbohydrate content of Scenedsmus. The research has proved that the best growing period for Scendsmue quadricauda is 15 days when using sugar factory waste as a carbon source, the growth reached (1.42 nm) as optical density, biomass (1525 mg /L), chlorophyll (green), pigment (18 mg /l) protein content (396 mg /l ) and carbohydrates ( 501 mg / l ). The research showed that the use of sugar factory waste as a nutritional medium for algal growth in the dark (11.5%) achieved good growth of Scendesmues quadricauda ( 0.632 nm), biomass (820 mg / L), green pigment (Chlorophyll) (18 mg /L) protein content (235 mg / L ) and carbohydrates (401 mg/L). while using phosphor (0.018%) of K2HPO4 in dark medium achieved highest growth rate (0.91 nm) , biomass (1110 mg / L) chlorophyll ( 22 mg/L) protein (301mg/L) and carbohydrate (461 mg/L) . It is noted too , that using IAA (0.5 g/L) in dark medium support best growth (0.888 nm) , biomass (1010 mg/L) chlorophyll (25 mg/L) , protein (230mg/L) and carbohydrate (440 mg//L) . The study showed that thiamine (1 g/L) in dark medium achieved highest growth (0.750 nm) biomass (218 mg/L), chlorophyll (29mg/L), protein (220 mg/L), carbohydrate (340mg/L). Therefore, using Molasses can enhance the growth, biomass, chlorophyll, protein, and carbohydrate content in the S. quadricauda.

Vitamin B12 (Cobalamin) and Micronutrient Fortification in Food Crops Using Nanoparticle Technology

It is necessary to develop a resilient food supply that will withstand unexpected future shocks and deliver the required amounts of nutrients to consumers. By increasing the sustainability of food and agriculture, the food system will be able to handle challenges such as climate change, declining agricultural resources, growing population/urbanization, pandemics, and recessions/shortages. Micronutrient deficiency, otherwise called hidden hunger, is one of the major malnutrition consequences worldwide, particularly in middle- or low- income countries. Unlike essential mineral or nutrient compounds, micronutrients could be less of a priority due to their small levels of requirement. However, insufficient micronutrients caused critical adverse health symptoms and are excessively vital for young children's development. Therefore, there have been numerous attempts to enhance minerals and nutrients in food crops, including biofortification, food fortification, and supplementation. Based on several interventions involving micronutrients, modern technology, such as nanotechnology, can be applied to enhance sustainability and to reduce the food system's environmental impact. Previous studies have addressed various strategies or interventions to mitigate major micronutrient deficiency including iron, iodine, zinc, and vitamin A. Comparably small amounts of studies have addressed vitamin B12 deficiency and its fortification in food crops. Vitamin B12 deficiency causes serious adverse health effects, including in the nervous or blood systems, and occurs along with other micronutrient deficiencies, such as folate, iron, and zinc, worldwide, particularly in middle- and low-income countries. Mitigation for B12 deficiency has mainly focused on developing pharmacological and medical treatments such as vitamin B12 serum or supplements. Further studies are required to undertake a sustainable approach to fortify vitamin B12 in plant-based food sources for public health worldwide. This review paper highlights nanoparticle application as a promising technology for enhancing vitamin B12 without conventional genetic modification requirements. The nanoparticle can efficiently deliver the mineral/nutrient using coating techniques to targeted sites into the plant. This is mainly because nanoparticles have better solubility and permeability due to their nano size with high surface exposure. Vitamin B12-coated nanoparticles would be absorbed, translocated, and accumulated by the plant and eventually enhance the bioavailability in food crops. Furthermore, by reducing adverse environmental effects, such as leaching issues that mainly occur with conventional fertilizer usage, it would be possible to develop more sustainable food fortification.

Evaluation of high salinity adaptation for lipid bio-accumulation in the green microalga Chlorella vulgaris

Aiming at the reutilizing wastewater for algal growth and biomass production, a saline water rejected from reverse osmosis (RO) facility (salinity 67.59 g L⁻¹) was used to cultivate the pre-adapted green microalga Chlorella vulgaris. The inoculum was prepared by growing cells in modified BG-11 medium, and adaptation was performed by applying a gradual increase in salinity (56.0 g L⁻¹ NaCl and 125 ppm FeSO₄·7H₂O) to the culture in 200 L photobioreactor. Experiments using the adapted alga were performed using original-rejected water (ORW) and treated rejected water (TRW) comparing with the recommended growth medium (BG-11). The initial salinity of ORW was chemically reduced to 39.1 g L⁻¹ to obtain TRW. Vertical photobioreactors (15 L) was used for indoor growth experiments. Growth in BG-11 resulted in 1.23 g L⁻¹, while the next adaptation growth reached 2.14 g L⁻¹ of dry biomass. The dry weights of re-cultivated Chlorella after adaptation were 1.49 and 2.19 g L⁻¹ from ORW and TRW; respectively. The cellular oil content was only 12% when cells grown under control conditions verses to 14.3 and 15.42% with original and treated water, respectively. Induction of stress affected the fatty acid methyl esters (FAMEs) profile and the properties of the resulting biodiesel. The present results indicated that induction of stress by high salinity improves the quality of FAMEs that can be used as a promising biodiesel fuel.

Improvement of ethanol production using green alga Chlorococcum minutum

Incessant depletion of fossil fuels urges the governments and non-governmental organizations to invest more on renewable energy sectors including generation of biofuels such as bioethanol. Production of ethanol from algal feedstock has been an interesting area of research in recent times. In the present investigation, feedstock of a green alga Chlorococcum minutum was selected for ethanol production and compared with feedstock of model alga Chlamydomonas reinhardtii. Both the species were grown under in vitro conditions using universal tris-acetate-phosphate (TAP) medium with various concentrations and combinations of vitamins such as thiamin, biotin and cobalamin (B1, B7 and B12) to enhance the biomass in turn reducing sugars in both the algal cultures. Later, these algal feedstocks were used for the production of ethanol under fermentation conditions using yeast. Reducing sugars were more in both the algal cultures grown in Cr3 or Cm3 media (TAP with 0.8 g/L of B1, 0.004 g/L of B7 & 0.004 g/L of B12) and also in Cr2 or Cm2 media (TAP with 0.4 g/L of B1, 0.002 g/L of B7 & 0.002 g/L of B12). In extent, the enhancement of ethanol production was noticed in C. reinhardtii (33.57 g/L) and C. minutum (46.97 g/L) from the feedstocks grown in Cr3 or Cm3 media when compared with feedstocks grown in other vitamin combinations or without vitamin assistance. Specifically, feedstock of C. minutum generated more output at 48 h when compared with model alga. The present work may be useful for the production of ethanol at a commercial level.

Production of Algal Biomass and High-Value Compounds Mediated by Interaction of Microalgal Oocystis sp. KNUA044 and Bacterium Sphingomonas KNU100

There is growing interest in the production of microalgae-based, high-value by-products as an emerging green biotechnology. However, a cultivation platform for Oocystis sp. has yet to be established. We therefore examined the effects of bacterial culture additions on the growth and production of valuable compounds of the microalgal strain Oocystis sp. KNUA044, isolated from a locally adapted region in Korea. The strain grew only in the presence of a clear supernatant of Sphingomonas sp. KNU100 culture solution and generated 28.57 mg/l/d of biomass productivity. Protein content (43.9 wt%) was approximately two-fold higher than carbohydrate content (29.4 wt%) and lipid content (13.9 wt%). Oocystis sp. KNUA044 produced the monosaccharide fucose (33 μg/mg and 0.94 mg/l/d), reported here for the first time. Fatty acid profiling showed high accumulation (over 60%) of polyunsaturated fatty acids (PUFAs) compared to saturated (29.4%) and monounsaturated fatty acids (9.9%) under the same culture conditions. Of these PUFAs, the algal strain produced the highest concentration of linolenic acid (C18:3 ω3; 40.2%) in the omega-3 family and generated eicosapentaenoic acid (C20:5 ω3; 6.0%), also known as EPA. Based on these results, we suggest that the application of Sphingomonas sp. KNU100 for strain-dependent cultivation of Oocystis sp. KNUA044 holds future promise as a bioprocess capable of increasing algal biomass and high-value bioactive by-products, including fucose and PUFAs such as linolenic acid and EPA.

High-throughput proteomics and metabolomic studies guide re-engineering of metabolic pathways in eukaryotic microalgae: A review

Eukaryotic microalgae are a rich source of commercially important metabolites including lipids, pigments, sugars, amino acids and enzymes. However, their inherent genetic potential is usually not enough to support high level production of metabolites of interest. In order to move on from the traditional approach of improving product yields by modification of the cultivation conditions, understanding the metabolic pathways leading to the synthesis of the bioproducts of interest is crucial. Identification of new targets for strain engineering has been greatly facilitated by the rapid development of high-throughput sequencing and spectroscopic techniques discussed in this review. Despite the availability of high throughput analytical tools, examples of gathering and application of proteomic and metabolomic data for metabolic engineering of microalgae are few and mainly limited to lipid production. The present review highlights the application of contemporary proteomic and metabolomic techniques in eukaryotic microalgae for redesigning pathways for enhanced production of algal metabolites.

Challenging microalgal vitamins for human health

BACKGROUND

Vitamins' deficiency in humans is an important threat worldwide and requires solutions. In the concept of natural biofactory for bioactive compounds production, microalgae represent one of the most promising targets filling many biotechnological applications, and allowing the development of an eco-sustainable production of natural bioactive metabolites. Vitamins are probably one of the cutting edges of microalgal diversity compounds.

MAIN TEXT

Microalgae can usefully provide many of the required vitamins in humans, more than terrestrial plants, for instance. Indeed, vitamins D and K, little present in many plants or fruits, are instead available from microalgae. The same occurs for some vitamins B (B12, B9, B6), while the other vitamins (A, C, D, E) are also provided by microalgae. This large panel of vitamins diversity in microalgal cells represents an exploitable platform in order to use them as natural vitamins' producers for human consumption. This study aims to provide an integrative overview on vitamins content in the microalgal realm, and discuss on the great potential of microalgae as sources of different forms of vitamins to be included as functional ingredients in food or nutraceuticals for the human health. We report on the biological roles of vitamins in microalgae, the current knowledge on their modulation by environmental or biological forcing and on the biological activity of the different vitamins in human metabolism and health protection.

CONCLUSION

Finally, we critically discuss the challenges for promoting microalgae as a relevant source of vitamins, further enhancing the interests of microalgal "biofactory" for biotechnological applications, such as in nutraceuticals or cosmeceuticals.

Tabrizicola algicola sp. nov. isolated from culture of microalga Ettlia sp

A novel Gram-stain-negative, aerobic, non-spore-forming, non-motile, and rod-shaped bacterium, strain ETT8^T was isolated from a chemostat culture of microalga Ettlia sp. YC001. Optimal growth was with 0-2% NaCl and at 25-37 °C on R2A medium. Phylogenetic analysis based on the 16S rRNA gene and genome sequence showed that strain ETT8^T belongs to the genus Tabrizicola, with the close neighbours being T. sediminis DRYC-M-16^T (98.1 %), T. alkalilacus DJC^T (97.6 %), T. fusiformis SY72^T (96.9 %), T. piscis K13M18^T (96.8 %), and T. aquatica RCRI19^T (96.5 %). The genomic comparison of strain ETT8^T with type species in the genus Tabrizicola was analysed using the genome-to-genome distance calculator (GGDC), average nucleotide identity (ANI), and average amino acid identity (AAI) (values indicated ≤17.7, ≤75.4 and ≤71.9 %, respectively). The genomic DNA G+C content of strain ETT8^T was 64.4 %, plus C_18 : 1  ω6c and C_18 : 0-iso were the major fatty acids and Q-10 the major respiratory quinone. Strain ETT8^T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine aminolipid, and four unidentified lipids as the major polar lipids. Based on the chemotaxonomic, genotypic, and phenotype results, strain ETT8^T was recognized as a novel species of the genus Tabrizicola for which the name Tabrizicola algicola sp. nov. is proposed. The type strain is ETT8^T (=KCTC 72206^T=JCM 31893^T=MCC 4339^T).

Immobilised Chlorella vulgaris as An Alternative for The Enhancement of Microalgae Oil and Biodiesel Production

Microalgae are a promising alternative for biodiesel production and a valuable source of fatty acid methyl ester (FAME). In this research, Chlorella vulgaris has been chosen as the suitable microalgae because this species was able to produce highest oils for biodiesel processing. Previously, sodium alginate (SA) was used to entrap the microalgae in the culturing process due to its low toxicity and high transparency. However, SA have some disadvantages such as bead disruption which leading to the loss of microalgae cell. Therefore, this research has been conducted to evaluate the oil production of immobilised Chlorella vulgaris using different matric systems at different ratios which are 0.3:1, 1:1 and 2:1. Currently, six matric systems have been developed, they are SA as a control, a combination of SA and chitosan (SA+CT), SA and carrageenan (SA+CR), SA and gelatin (SA+GT), SA and calcium alginate (SA+CA), and SA and sodium carboxymethylcellulose (SA+CMC). The microalgae was first cultivated, harvested and extracted to produce oil, prior to use in the transesterification process. The SA+GT showed the highest oil yield with 59.14% and a total FAME of 0.56 mg/g. The FAME profile of oil extracted microalgae showed high potential for biodiesel production as it consisted of palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). The results proved that the combination of SA+GT had improved the oil yield and fatty acid composition as compared to the other matric systems, which may have useful application for the biodiesel industry. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Synergism between the Black Queen effect and the proteomic constraint on genome size reduction in the photosynthetic picoeukaryotes

The photosynthetic picoeukaryotes (PPEs) comprise a rare example of free-living eukaryotes that have undergone genome reduction. Here, we examine a duality in the process; the proposed driver of genome reduction (the Black Queen hypothesis, BQH), and the resultant impact of genome information loss (the Proteomic Constraint hypothesis, PCH). The BQH predicts that some metabolites may be shared in the open ocean, thus driving loss of redundant metabolic pathways in individual genomes. In contrast, the PCH predicts that as the information content of a genome is reduced, the total mutation load is also reduced, leading to loss of DNA repair genes due to the resulting reduction in selective constraint. Consistent with the BQH, we observe that biosynthetic pathways involved with soluble metabolites such as amino acids and carotenoids are preferentially lost from the PPEs, in contrast to biosynthetic pathways involved with insoluble metabolites, such as lipids, which are retained. Consistent with the PCH, a correlation between proteome size and the number of DNA repair genes, and numerous other informational categories, is observed. While elevated mutation rates resulting from the loss of DNA repair genes have been linked to reduced effective population sizes in intracellular bacteria, this remains to be established. This study shows that in microbial species with large population sizes, an underlying factor in modulating their DNA repair capacity appears to be information content.

Highest accumulated microalgal lipids (polar and non-polar) for biodiesel production with advanced wastewater treatment: Role of lipidomics

Microalgal lipids consist of non-polar and polar lipids. Triacyleglyceride (TAG), a non-polar lipid, is convertible to biodiesel, whereas glycolipids and phospholipids are polar and not convertible to biodiesel owing to their high degree of unsaturation (polyunsaturated fatty acids), which makes the production process insufficient and expensive. In this review, microalgal species that contain the highest lipid content (≥40%) in the literature till 2019 are highlighted. The differentiation between non-polar and polar lipids and the limitations in the conversion of polar lipids to biodiesel are reported. The basic and advanced factors contributing to the accumulation of lipids convertible to biodiesel is discussed. Microalgal species including Scenedesmus obliquus, Ourococcus multisporus, Chlamydomonas pitschmannii, Micractinium reisseri, and Botryococcus braunii with high lipid content are potential candidates for biomass/biodiesel production and nutrient removal from wastewater. Application of lipidomics and transcriptomics to manipulate the lipid associated gene acetyl-CoA synthetase in microalgae improves the accumulative lipid content.

Bioproducts From Euglena gracilis: Synthesis and Applications

In recent years, the versatile phototrophic protist Euglena gracilis has emerged as an interesting candidate for application-driven research and commercialisation, as it is an excellent source of dietary protein, pro(vitamins), lipids, and the β-1,3-glucan paramylon only found in euglenoids. From these, paramylon is already marketed as an immunostimulatory agent in nutraceuticals. Bioproducts from E. gracilis can be produced under various cultivation conditions discussed in this review, and their yields are relatively high when compared with those achieved in microalgal systems. Future challenges include achieving the economy of large-scale cultivation. Recent insights into the complex metabolism of E. gracilis have highlighted unique metabolic pathways, which could provide new leads for product enhancement by genetic modification of the organism. Also, development of molecular tools for strain improvement are emerging rapidly, making E. gracilis a noteworthy challenger for microalgae such as Chlorella spp. and their products currently on the market.

New Drugs from the Sea: Pro-Apoptotic Activity of Sponges and Algae Derived Compounds

Natural compounds derived from marine organisms exhibit a wide variety of biological activities. Over the last decades, a great interest has been focused on the anti-tumour role of sponges and algae that constitute the major source of these bioactive metabolites. A substantial number of chemically different structures from different species have demonstrated inhibition of tumour growth and progression by inducing apoptosis in several types of human cancer. The molecular mechanisms by which marine natural products activate apoptosis mainly include (1) a dysregulation of the mitochondrial pathway; (2) the activation of caspases; and/or (3) increase of death signals through transmembrane death receptors. This great variety of mechanisms of action may help to overcome the multitude of resistances exhibited by different tumour specimens. Therefore, products from marine organisms and their synthetic derivates might represent promising sources for new anticancer drugs, both as single agents or as co-adjuvants with other chemotherapeutics. This review will focus on some selected bioactive molecules from sponges and algae with pro-apoptotic potential in tumour cells.

Developments of Cyanobacteria for Nano-Marine Drugs: Relevance of Nanoformulations in Cancer Therapies

Current trends in the application of nanomaterials are emerging in the nano-biotechnological sector for development of medicines. Cyanobacteria (blue-green algae) are photosynthetic prokaryotes that have applications to human health and numerous biological activities as dietary supplements. Cyanobacteria produce biologically active and chemically diverse compounds such as cyclic peptides, lipopeptides, fatty acid amides, alkaloids, and saccharides. More than 50% of marine cyanobacteria are potentially exploitable for the extraction of bioactive substances, which are effective in killing cancer cells by inducing apoptotic death. The current review emphasizes that not even 10% of microalgal bioactive components have reached commercialized platforms due to difficulties related to solubility. Considering these factors, they should be considered as a potential source of natural products for drug discovery and drug delivery approaches. Nanoformulations employing a wide variety of nanoparticles and their polymerized forms could be an emerging approach to the development of new cancer drugs. This review highlights recent research on microalgae-based medicines or compounds as well as their biomedical applications. This review further discusses the facts, limitations, and commercial market trends related to the use of microalgae for industrial and medicinal purposes.