Isolation Of Microalgae Research Articles

Isolation, Extraction of Oil and Production of Biodiesel from Microalgae

This work is aimed at producing biodiesel from microalgae using Bold Basal Medium. After a month of cultivation, isolation, and harvesting, the microalgae were processed (oil was extracted using a chemical extraction procedure including alcohol with a 96% alcohol content and n-hexane). Transesterification was employed to produce the biodiesel from the extracted algal oil, and the resulting fuel was characterized. The results show that Chlorella sp, Desmid sp and Ankistrodesmus sp were isolated, density, viscosity, acid value, saponification, free fatty acid, peroxide value, iodine value, impurity level, and moisture content of Chlorella sp, Desmid sp and Ankistrodesmus sp oil were (0.805, 0.702, 0.716), (4.92, 4.45, 4.22), (1.51, 1.61, 1.62), (179.8, 178.61, 186.60), (0.86, 0.87, 0.88), (28.6, 28.9, 28.8), (0.31, 0.35, 0.33), (0.90, 0.80, 0.88) and (0.30, 0.36, 0.24) respectively, biodiesel had cetane number (126,125,127), density (0.79, 0.88, 0.87), flash point (126, 127, 125), calorific value (38.39, 38.68, 38.72), and viscosity (2.43, 2.66, 2.33) respectively, the quantity of biodiesel produced varied across all the replicates as the mean difference were less than the standard mean of 2.074. The production of biodiesel is practically possible in Nigeria, and the government should set up companies so as to diversify the oil sector and reduce pollution. The major limitation in this research work was using the traditional method for the isolation and identification of dominant microalgae instead of the molecular method.

Functional Analysis of the Channelrhodopsin Genes from the Green Algae of the White Sea Basin

Optogenetics, the method of light-controlled regulation of cellular processes is based on the use of the channelrhodopsins that directly generate photoinduced currents. Most of the channelrhodopsin genes have been identified in the green microalgae Chlorophyta, and the demand for increasing the number of functionally characterized channelrhodopsins and the diversity of their photochemical parameters keeps growing. We performed the expression analysis of cation channelrhodopsin (CCR) genes in natural isolates of microalgae of the genera Haematococcus and Bracteacoccus from the unique Arctic Circle region. The identified full-length CCR transcript of H. lacustris is the product of alternative splicing and encodes the Hl98CCR2 protein with no photochemical activity. The 5′-partial fragment of the B. aggregatus CCR transcript encodes the Ba34CCR protein containing a conserved TM1-TM7 membrane domain and a short cytosolic fragment. Upon heterologous expression of the TM1-TM7 fragment in CHO-K1 cell culture, light-dependent current generation was observed with the parameters corresponding to those of the CCR. The first discovered functional channelrhodopsin of Bracteacoccus has no close CCR homologues and may be of interest as a candidate for optogenetics.

Isolation and identification of marine microalgae from Egyptian coasts as potential source of biodiesel: morphology and sequence-based screening

ABSTRACT Microalgae are a highly effective and renewable source of biodiesel that can be used as a substitute for petro-diesel in the global fuel market. In the present study, 14 water samples were collected from a variety of locations along the coastal areas of the Red Sea and the Mediterranean Sea in Egypt. These water samples, which contained microalgae, were subjected to enrichment process and standard procedures to obtain pure cultures. Based on morphological features, 27 microalgae isolates representing 12 different species were identified, with Chlorella species being the most dominant. Based on 18s rRNA gene sequencing, nine new native microalgae strains were identified, comprising four strains belonging to Chlorella species, two strains to Chlamydomonas, and one strain each of Phormidium, Nostoc, and Microcytosis species that could be appropriate for producing biodiesel. This information could be used to improve the knowledge on the composition of planktonic microalgal communities of Egypt and the target native species for biodiesel production.

Isolation and characterization of native microalgae with potential for phycoremediation of heavy metal contaminated water

ABSTRACT The capacity of living algal cells to efficiently eliminate metals from water is well known and achieved through the mechanisms of biosorption and bioaccumulation. These investigations highlight the potential of indigenous microalgae for the elimination of toxic elements such as cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb) from aqueous solutions. To identify algal strains that are effective in removing heavy metals, samples of soil and water were collected from areas contaminated with industrial and municipal effluents. Among the 11 isolates obtained from various sites contaminated with heavy metals, three isolates (designated as A, I and K) were able to tolerate both the threshold and double threshold levels of the tested heavy metals. Subsequent liquid assays confirmed the efficiency of the three selected algal isolates in removing heavy metals, with isolates A and I demonstrating effectiveness in removing all tested heavy metals, exhibiting removal rates of cadmium ranging from 40% to 80%, cobalt ranging from 20% to 60%, chromium up to 90%, nickel ranging from 40% to 90%, and lead ranging from 50% to 70%. Isolate K displayed the highest efficiency in only removing lead, specifically 86.23% at 21 DAI (Days After Inoculation), and therefore was not chosen for further characterization. Through morphological and molecular characterization, isolates A and I were identified as Coelastrella thermophila AAU BR A and Chlorella sp. AAU BR I, respectively. In conclusion, the results demonstrate that the native algal isolates have the potential to serve as eco-friendly agents for remediating heavy metal-contaminated water.

Lipid Yields and Fatty Acid Composition if Indigenous Microalgae, Isolated from the Beira, and Diyawanna Urban Lakes, for Sustainable Biofuel Production in Sri Lanka


 Biofuels are carbon-neutral combustibles produced from renewable biomass. Third generation biofuels, derived from microalgal biomass, are distinctly superior to their preceding generations, due to higher productivity and resource use efficiency of microalgae compared to conventional energy crops. It is a viable source of sustainable energy for our country due to the availability of water, ambient temperatures and year-round sunlight needed for microalgae cultivation, and most importantly, the abundance of diverse microalgae species. However, these native microalgae are relatively unexplored for their productivities and thereby, greatly underutilized. This research was aimed to investigate the lipid yields and fatty acid compositions of local freshwater microalgae, and to identify their potential for biodiesel production. This was carried out by (1) microalgae isolation and morphological identification (2) microalgae cultivation (3) biomass harvesting, lipid extraction, gravimetric measurement of extracted lipids and (4) acid-catalysed transesterification, followed by GCMS analysis of the biodiesel product. Chlorella sp., Chlorococcum sp. and Chlamydomonas sp. were isolated from Beira/ Diyawanna Lakes using streak plate technique in solid standard BBM media. They were next cultivated under axenic conditions in liquid standard BBM media under 16: 8 (light: dark), at 25°C for 20 days in duplicates. The biomass was then harvested using alum, dried to reach a constant weight and the Bligh and Dyer lipid extraction was done in triplicate. The extracted lipids were trans-esterified with methanol, using sulfuric acid catalyst at 90° C for 60 minutes. The separated product was analysed by GCMS. Chlorella sp., Chlorococcum sp. and Chlamydomonas sp. cultivated under standard conditions gave average lipid yields of 11.34±1.01%, 15.00±1.40% and 2.10±0.50% respectively. Average lipid yield of Chlamydomonas sp. was significantly lower than the other two species at 95% confidence level (Two-sample T test on SPSS Version 21). GCMS analysis of the biodiesel product from Chlorella sp. indicated significant levels of saturated fatty acids including palmitic and stearic acids, monounsaturated fatty acids like cis-11- eicosenoic acid and polyunsaturated fatty acids including linoleic and linolenic acids. The fatty acid ratios were used to calculate the saturation value, cetane number, density, iodine value and pour point of the produced biodiesel. These quality parameters were in accordance with the ASTM D6751- 20a standards. Therefore, with a substantial yield and fatty acid composition of intracellular lipids, this local species of Chlorella can be a prospective candidate for sustainable bioenergy production in Sri Lanka.
 
 Keywords: Chlorella, Chlorococcum, Chlamydomonas, Microalgal lipids, Biodiesel

Isolation and Identification of Green Microalgae from Northern Jordan

In light of the rapid and extreme changes in climate and the steady depletion of natural resources, there is an urgent need to find innovative and sustainable solutions to these problems. Microorganisms such as microalgae can offer viable solutions to these challenges. Proper investment in such organisms requires the identification of the algal species that inhabit the region. Therefore, this study aimed to isolate and molecularly characterize green microalgae that inhabit freshwater at different locations in the governorates of Irbid and Ajloun in the northern region of Jordan. Water samples collected from these regions were used to isolate single colonies, some of which exhibited different morphological characteristics. Genomic DNA was extracted from the isolates and used as a template for PCR amplification of the 18S ribosomal DNA gene (18S rDNA) and the internal transcribed spacer (ITS) region. Phylogenetic trees were constructed based on 18S rDNA and ITS PCR product sequences, which were used to identify the isolates at the genus level. The obtained isolates belonged to three genera; Coelastrella, Desmodesmus, and Monoraphidium. The latter species has not been previously reported in Jordan.

Remoción de nitrógeno y fósforo acoplada a la fijación de CO2 de dos microalgas verdes, Chlorella sp. y Quadrigula sp., nativas de la costa de Chiapas, México

Microalgae remove nitrogen and phosphorus from water for their growth and biomass production, wich has several biotechnological applications. This study evaluated the growth, NO3−, NO2−, NH4+, urea, PO43− and total nitrogen removal capacity, as well as the biomass production and the CO2 fixation of two new microalgae isolates, Chlorella sp. and Quadrigula sp., from the coast of Chiapas, México. Chlorella sp. had a higher specific growth rate (0.74/day) and a shorter doubling time (0.92 days) than Quadrigula sp. Removal per unit volume (mg/L) of NO3−, NH4+ and total nitrogen by Chlorella sp. was higher (26.88%, 10.58% and 16.63%, respectively) than removal by Quadrigula sp. On the other hand, daily removal (mg/L/d) of NO3−; NH4+; NO2−; urea and total nitrogen by Chlorella sp. was also higher (88%, 33%, 89%,15% and 50%, respectively) than daily removal by Quadrigula sp. The biomass productivity (mg/L/d) and the CO2 fixation rate (mg/L/d) were similar among both microalgae. The results of this study suggest that Chlorella sp. and Quadrigula sp. have potential for nutrient removal, biomass production and CO2 fixation.

Identification and Characterization of a Novel Microalgal Strain from the Antofagasta Coast Tetraselmis marina AC16-MESO (Chlorophyta) for Biotechnological Applications.

The wide rocky coastline of the Antofagasta hosts an intertidal ecosystem in which the species that inhabit it are routinely exposed to a wide range of physical and chemical conditions and have therefore evolved to tolerate extremes. In the search for new species of potential biotechnological interest with adaptations to a wide range of environmental conditions, the isolation and characterization of microalgae from these ecosystems is of great interest. Here, a new microalgal strain, Tetraselmis marina AC16-MESO, is described, which was isolated from a biofilm collected on the intertidal rocks of the Antofagasta coast (23°36'57.2″ S, 70°23'33.8″ W). In addition to the morphological characterization, 18S and ITS sequence as well as ITS-2 secondary structure analysis revealed an identity of 99.76% and 100% with the species Tetraselmis marina, respectively. The analyses of the culture characteristics and biochemical content showed similarities with other strains that are frequently used in aquaculture, such as the species Tetraselmis suecica. In addition, it is tolerant of a wide range of salinities, thus allowing its culture in water of varying quality. On the other hand, added to these characteristics, the results of the improvement of the lipid content in stressful situations of salinity observed in this study, together with other antecedents such as the potential in bioremediation already published for this strain by the same research group, present a clear example of its biotechnological plasticity. It is noteworthy that this strain, due to its characteristics, allows easy collection of its biomass by decantation and, therefore, a more cost-efficient harvesting than for other microalgal strains. Therefore, this new strain of Tetraselmis marina, first report of this species in Chile, and its morphologically, molecularly and biochemically description, presents promising characteristics for its use in biotechnology and as feed for aquaculture.

Isolation and characterization of soil cyanobacteria and microalgae and evaluation of their potential as plant biostimulants

Background and AimsBiocrusts are found on soil surface resulting from an association between soil particles and microorganisms. Photoautotrophic cyanobacteria and microalgae are pioneers on biocrusts formation, promoting soil stability, nutrients availability and water retention, leading to the development of other communities. This work aimed at isolating and characterizing cyanobacteria/microalgae from biocrusts (Central Portugal) and to assess their potential as plant biostimulants, as well as obtaining an insight into their mechanism(s) of action.MethodsMicroorganisms were isolated through successive spread plating/serial dilutions and characterized using genetical analysis/morphological traits. An initial screening was performed using exudates from each microorganism and two plant species, Arabidopsis thaliana and Lolium multiflorum. Subsequently, the selected microorganisms were tested as a consortium in hydroponic systems. Biometric and biochemical parameters were evaluated for both plant species.ResultsThe consortium microorganisms belong to genera often found in soils/biocrusts: Trichocoleus, Nodosilinea, Microcoleus (filamentous cyanobacteria), Nostoc (diazotrophic heterocystous cyanobacteria), and Klebsormidium (filamentous microalga), and some of them have the capacity to produce phytohormones and/or siderophores. The consortium showed biostimulant potential in hydroponic cultures, promoting plant growth and enhancing physiological productivity related parameters. Stress related parameters revealed that the microorganisms did not lead to a stressful situation. However, a significant increase in proline was observed, endorsing a role of this molecule in this process.ConclusionThis study contributes to the knowledge on the biodiversity of cyanobacteria and microalgae from Portuguese soils and highlights their potential as biostimulants, constituting a step forward towards understanding the molecular mechanisms behind this effect.

Isolation of phosphorus-hyperaccumulating microalgae from revolving algal biofilm (RAB) wastewater treatment systems.

Excess phosphorus (P) in wastewater effluent poses a serious threat to aquatic ecosystems and can spur harmful algal blooms. Revolving algal biofilm (RAB) systems are an emerging technology to recover P from wastewater before discharge into aquatic ecosystems. In RAB systems, a community of microalgae take up and store wastewater P as polyphosphate as they grow in a partially submerged revolving biofilm, which may then be harvested and dried for use as fertilizer in lieu of mined phosphate rock. In this work, we isolated and characterized a total of 101 microalgae strains from active RAB systems across the US Midwest, including 82 green algae, 9 diatoms, and 10 cyanobacteria. Strains were identified by microscopy and 16S/18S ribosomal DNA sequencing, cryopreserved, and screened for elevated P content (as polyphosphate). Seven isolated strains possessed at least 50% more polyphosphate by cell dry weight than a microalgae consortium from a RAB system, with the top strain accumulating nearly threefold more polyphosphate. These top P-hyperaccumulating strains include the green alga Chlamydomonas pulvinata TCF-48 g and the diatoms Eolimna minima TCF-3d and Craticula molestiformis TCF-8d, possessing 11.4, 12.7, and 14.0% polyphosphate by cell dry weight, respectively. As a preliminary test of strain application for recovering P, Chlamydomonas pulvinata TCF-48 g was reinoculated into a bench-scale RAB system containing Bold basal medium. The strain successfully recolonized the system and recovered twofold more P from the medium than a microalgae consortium from a RAB system treating municipal wastewater. These isolated P-hyperaccumulating microalgae may have broad applications in resource recovery from various waste streams, including improving P removal from wastewater.

Prospecting the biofuel potential of new microalgae isolates

The continued search and urgent need for renewable fuel sources have necessitated the exploration of microalgae to identify relevant species for making biofuels. The aim of the study was bioprospecting and screening native microalgae strains from freshwater habitats of the Almaty region, Kazakhstan, to assess the potential for producing biofuel. The studied strains demonstrated simultaneous biomass productivity, lipid productivity, suitable fatty acid composition, and biodiesel properties. The sequence analysis of the ribosomal DNA internal transcribed spacer partial region and ribulose-bisphosphate carboxylase gene (rbcL) led to the identification of five microalgae: Monoraphidium griffithii ZBD-01, Nephrochlamys subsolitaria ZBD-02, Ankistrodesmus falcatus ZBD-03, Parachlorella kessleri ZBD-04, and Desmodesmus pannonicus ZBD-05. P. kessleri had the highest biomass production (1.42 ± 0.08 g L−1 day−1), lipid productivity (29 ± 1.2 g L−1day−1), and C16–C18 fatty acid contents (90%), followed by A. falcatus and M. griffithi. Gas chromatography/mass spectrometry analysis indicated that the dominant fatty acids in these strains were palmitic, stearic, and oleic acids. The calculated biodiesel properties of P. kessleri and A. falcatus based on fatty acid methyl esters (FAME) profiles showed relatively good fuel properties (cetane numbers - 48 and 50; iodine and saponification values - 83.4 and 103.6 g I₂/100 g oil, 260.8 and 199.5 mg KOH g−1), which correlate well with. Our results suggest that P. kessleri and A. falcatus are promising strains for biodiesel production due to their high lipid productivity, fatty acid profile with relatively high content of oleic acid, and suitable biodiesel properties. The isolated native species of microalgae from natural freshwater bodies of the Almaty region present opportunities for further exploitation for the sustainable production of biomass and biodiesel.

Biocoagulation of Dried Algae Chlorella sp. and Pellets of Aspergillus Niger in Decontamination Process of Wastewater, as a Presumed Source of Biofuel.

The removal of microalgae represents a problematic part of the water decontamination process, in which most techniques are expensive and non-ecological. In the paper, we focus on the synergistic relationship between microscopic filamentous fungi and algal culture. In the process of decontamination of a model sample containing ammonium ions, efficient biocoagulation, resp. co-pelletization of dried algae Chlorella sp. and Aspergillus niger sensu stricto are shown. The microscopic filamentous fungus species A. niger was added to a culture of an algal suspension of Chlorella sp., where the adhesion of the algal cells to the fungi subsequently occurred due to the electrostatic effect of the interaction, while the flocculation activity was approximately 70 to 80%. The algal cells adhered to the surface of the A. niger pellets, making them easily removable from the solution. The ability of filamentous fungi to capture organisms represents a great potential for the biological isolation of microalgae (biocoagulation) from production solutions because microalgae are considered to be a promising renewable source of oil and fermentables for bioenergy. This form of algae removal, or its harvesting, also represents a great low-cost method for collecting algae not only as a way of removing unnecessary material but also for the purpose of producing biofuels. Algae are a robust bioabsorbent for absorbing lipids from the environment, which after treatment can be used as a component of biodiesel. Chemical analyses also presented potential ecological innovation in the area of biofuel production. Energy-efficient and eco-friendly harvesting techniques are crucial to improving the economic viability of algal biofuel production.

Biological characteristics of the heterotrophic marine microalgae Thraustochytrium pachydermum TSL10 isolated from the sea area of Truong Sa Archipelago, Vietnam

The sea area of the Truong Sa Archipelago, Vietnam - outpost island region of the country has a special geographical location and plays an important role in economic development as well as security and defense of Vietnam. Here, the first time for isolation of heterotrophic marine microalgae is precious. In this paper, the results on isolation, identification, and selection of suitable culture conditions of the strain Thraustochytrium pachydermum TSL10 isolated from the sea area of Spratly Island, Truong Sa Archipelago, Vietnam in 2021 were presented. The optimal culture conditions for the growth of T. pachydermum TSL10 in the flask were M1 medium, 3% glucose, 1% yeast extract and 25 - 28 °C temperature. Dry biomass and lipid content reached the highest levels of 12.54 ± 1.23 g/L and 28.65 ± 1.11 % dry cell weight (DCW), respectively. In a 30 L fermentor, T. pachydermum TSL10 grew well in a medium containing 9% glucose and 1% industrial extract yeast. After 120 hours of cultivation, dry biomass, lipid, protein, carbohydrate, carotenoids, and astaxanthin reached the highest levels of 30.76 ± 1.32 g/L; 22.95 ± 0.28% DCW; 6.65 ± 0.19% DCW, 15.96 ± 0.021% DCW, 178.00 ± 2.43 µg/L, and 8.30 ± 0.28 µg/L, respectively. The fatty acid composition contains mainly omega - 6 and omega - 9 fatty acids, accounting for 21.69% of total fatty acids (TFA) and 34.56% of TFA. The fatty acid profile was mainly dominated by linoleic acid and oleic acid, accounting for 21.54% of TFA and 34.23% of TFA, respectively. The results showed that TSL10 biomass was suitable raw material for screening bioactive compounds.

COLLECTION, ISOLATION, PURIFICATION AND IDENTIFICATION OF MICROALGAE FROM PADDY SOIL AT KADAWA IRRIGATION FARMLAND, KANO STATE

The success of any microalgal research involves effective methods for sampling environments, isolation, purification and the maintenance of algal strains. The isolation of soil microalgae poses a great challenge since the soil is a home for thousands of different species, including algal species, bacteria, viruses and fungi. As such cultures are susceptible to contamination, which may interfere with algal structure, biomass yield and the erroneous identification of species for molecular genetic analysis. The most common methods for isolation and purification of microalgae are the single cell isolation, serial dilution and a streak plate. This procedure is tedious, time consuming, demands precision and expertise and may not yield results. Thus in the present study, an attempt was made to modify these methods for the isolation of soil microalgae. With the modification, three microalgal sp. were isolated, purified and identified (viz Chlorella vulgaris, Microcystis aeruginosa and Scenedesmus obliquus) in a simplified manner.

Bioremoval capacity of Co+2 using Phormidium tenue and Chlorella vulgaris as biosorbents.

Microalgae sorbents are microalgae that have the potential to passively bind heavy metals/contaminants to their cellular structures in a process called biosorption. This study investigates the use of two species of microalgae to remove the toxic heavy metal cobalt from aqueous solution. Two microalgae isolates, Phormidium tenue and Chlorella vulgaris, were collected from the Wadi Hanifah Stream in Riyadh, the Kingdom of Saudi Arabia. We determined the capacity of both isolates to bioremove Co+2 ions and the optimum conditions under which this occurs. The two isolates were additionally characterized by microscopic and Fourier transform infrared spectroscopy (FTIR). In the current investigation, Phormidium tenue removed 94% of Co+2 under ideal conditions of pH 6, contact duration (30min), starting concentration (50mgL-1) and biosorbent dose (1gL-1); while Chlorella vulgaris removed 87% of Co+2 under the same parameters except pH 5.5 and contact duration (60min). Fourier transform infrared spectroscopy (FTIR) confirms the binding of Co+2 to the biomass, which comprises many of the functional groups. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed some alterations to the shape of algal cells and cellular components for both microalgae studied. In addition, equilibrium study by both Langmuir and Freundlich models was performed to detect the effect of certain equilibrium factors on the capacity of the biosorption mechanism. Finally, Phormidium tenue and Chlorella vulgaris were discovered to be promising microalgae for effective cobalt biosorption in aquatic conditions.

Comparison of different pretreatment methods to facilitate the carbohydrate release from two microalgae isolates: a critical step in bioethanol production

Comparison of different pretreatment methods to facilitate the carbohydrate release from two microalgae isolates: a critical step in bioethanol production

Bioprocess of of Astaxanthin Production as Functional Food from Aurantiochytrium Microalgae: A Review

The Covid-19 pandemic has increased human needs for nutrition including functional food and nutraceutical products in line with the need to boost immunity to resist viral infection, maintain a healthy life, and limit fatalities. In this regard, the choice to use functional food and nutraceuticals seems to be a promising panacea. This paper aims to examine the potential of the microalgae species Aurantiochytrium, which is commonly found in the mangrove ecosystem. This microalgae species has received a lot of attention from researchers because of its high content of lipids and other high-value-added components as well as its fast growth and resistance to environmental stress. With current bioprocess technology, Aurantiochytrium microalgae can be deployed to produce high-value-added components such as astaxanthin. During the current pandemic, the need for this product is increasing as raw material for drugs, health supplements, antioxidants, and vaccine adjuvants that are in direct contact with efforts to combat the human coronavirus and prevent the spread of viral diseases. In general, producing functional nutritional products from  Aurantiochytrium microalgae requires several stages starting from the isolation and screening of microalgae, cultivation, extraction of the desired components and finally downstream processing for purification and packaging the product. Although Aurantiochytrium microalgae is found in the mangrove ecosystem, unfortunately, studies on the production potential of functional nutrients from microalgae Aurantiochytrium native strains from Indonesia have been rarely pubslihed. Therefore, it is expected that this study will become a fundamental basis for further research in this field and increasing attention for the production of functional nutrients from  Aurantiochytrium microalgae isolated from mangrove forests in Indonesia. An early insight into bioprocess technology modes such as appropriate isolation techniques, cultivation, and extraction to produce astaxanthin is provided.

Fast-Tracking Isolation, Identification and Characterization of New Microalgae for Nutraceutical and Feed Applications

Microalgae contain high-value biochemical compounds including fatty acids (FA), protein and carotenoids, and are promising bioresources to enhance nutrition of food and animal feed. Important requirements for commercial strains are rapid growth and high productivities of desirable compounds. As these traits are believed to be found in aquatic environments with fluctuating conditions, we collected microalgae from marine and freshwater environments that are subjected to eutrophication and/or tidal fluctuations. Using this directed approach, 40 monoalgal cultures were isolated and 25 identified through 18S rDNA sequencing and morphological characterization. Based on their high growth rates (0.28–0.60 day−1) and biomass productivities (0.25–0.44 g L−1 day−1) in commercial fertilizer under standardized conditions, six new strains were selected. Scenedesmus sp. GW63 produced quality FA-rich biomass with high omega-3 polyunsaturated FA (28.5% of total FA (TFA)) contents, especially α-linolenic acid (ALA; 20.0% of TFA) with a very low n-6/n-3 ratio (0.4), and high FA productivity (32.6 mg L−1 day−1). A high protein productivity (34.5 mg L−1 day−1) made Desmodesmus sp. UQL1_26 (33.4% of dry weight (DW)) attractive as potential protein-rich feed and nutrition supplement. Monoraphidium convolutum GW5 displayed valuable carotenoid production (0.8% DW) with high carotenoid accumulation capability (0.8 mg L−1 day−1). This research provides a pathway for fast-tracking the selection of high-performing local microalgae from different environments for nutraceuticals, functional foods and animal feed applications.

ISOLATION OF MICROALGAE FROM ANTARCTIC SOIL

Microalgae are unicellular photosynthetic microorganisms which are able to survive in extreme environmental conditions, specifically low temperature, high evaporation rates as well as low water availability. Polar microalgae from the Antarctic region have received attention from researchers due to their special adaptations for surviving in extremely cold environments and being isolated from various types of samples. Four Antarctic soil samples were used on this study namely-Sample A, Sample B, S18 and S30. All soil samples were subjected to serial dilution and spread on BBM followed by 3 weeks incubation at 25oC with periodic light. Only soil sample S30 showed positive microalgae growth after additional 3 weeks incubation period. Consequently, soil sample S30 was proceeded to isolation of microalgae using BBM, 3N- BBM+V, JM and MWC media. Observable growth of green microalgae could only be obtained using 3N-BBM+V and JM media. Moreover, 3N-BBM+V medium successfully produced the highest number of microalgae colonies recovered from Antarctic soil sample. Isolation of microalgae from Antarctic provides resources for various industrial and commercial applications.

Morphological Observation, Identification and Isolation of Tropical Marine Microalgae from Ambon Bay, Maluku

Microalgae are photosynthetic microorganisms that are widely distributed in waters. They have the potential as an alternative source of pigments, lipids, proteins, and carbohydrates. In this study, identification and isolation of single-cell microalgae from Ambon Bay were carried out by serial dilution method and inoculation of the culture by appearance/spread on the surface of the solidified agar medium. The results showed that the waters of Ambon Bay have physical parameters such as temperature, pH, salinity, and TDS, which are still within the threshold specified in the seawater quality standard for biota. The water conditions at the 10 sampling locations had different salinity, pH, temperature, and TDS. This condition affects the distribution of microalgae in the waters in Ambon Bay. The image from light microscopy shows that there are 27 species of microalgae scattered in the waters of Ambon Bay, which belong to the classes Chlorophyceae, Flagilariophyceae, Bacillariophyceae (diatoms), Coscinodiscophyceae, and Dinophyceae. Microalgae isolation obtained five species (single-cell) including four species from the class Bacillariophyta (Navicula sp, Nitzschia sp, Cyclotella sp) and one species from the class Chlorophyta (Chlorella sp).