Displaying publications 61 - 80 of 243 in total

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  1. Harvesting of the Microalga Nannochloropsis sp. by Bioflocculation with Mung Bean Protein Extract
    Kandasamy G, Shaleh SRM
    Appl Biochem Biotechnol, 2017 Jun;182(2):586-597.
    PMID: 27957653 DOI: 10.1007/s12010-016-2346-7
    Harvesting microalgae from medium is a major challenge due to their small size and low concentrations. In an attempt to find a cost-effective and eco-friendly harvesting technique, mung bean (Vigna radiata) protein extract (MBPE) was used for flocculation of Nannochloropsis sp. The effects of parameters such as pH, flocculant dose, algae concentration, and mixing time were used to study the flocculation efficiency (FE) of MBPE. Optimum parameters of MBPE dosage of 20 mL L(-1) and a mixing rate of 300 rpm for 6 min achieved a FE of >92% after 2 h of settling time. MBPE-aggregated microlga flocs were characterized by microscopy. Zeta potential values decreased with increasing flocculant dose, and the values obtained were -6.93 ± 0.60, -5.36 ± 0.64, and -4.44 ± 0.22 for doses of 10, 20, and 30 mL L(-1), respectively. In conclusion, MBPE flocculants used in this study are safe, nontoxic, and pollution free, so they could be used for an effective, convenient, and rapid harvesting of microalgae in an eco-friendly approach. These methods are sustainable and could be applied in industrial scale for aquaculture nutrition.
    Matched MeSH terms: Microalgae/isolation & purification*
  2. Flotation removal of the microalga Nannochloropsis sp. using Moringa protein-oil emulsion: A novel green approach
    Kandasamy G, Shaleh SRM
    Bioresour Technol, 2018 Jan;247:327-331.
    PMID: 28950142 DOI: 10.1016/j.biortech.2017.08.187
    A new approach to recover microalgae from aqueous medium using a bio-flotation method is reported. The method involves utilizing a Moringa protein extract - oil emulsion (MPOE) for flotation removal of Nannochloropsis sp. The effect of various factors has been assessed using this method, including operating parameters such as pH, MPOE dose, algae concentration and mixing time. A maximum flotation efficiency of 86.5% was achieved without changing the pH condition of algal medium. Moreover, zeta potential analysis showed a marked difference in the zeta potential values when increase the MPOE dose concentration. An optimum condition of MPOE dosage of 50ml/L, pH 8, mixing time 4min, and a flotation efficiency of greater than 86% was accomplished. The morphology of algal flocs produced by protein-oil emulsion flocculant were characterized by microscopy. This flotation method is not only simple, but also an efficient method for harvesting microalgae from culture medium.
    Matched MeSH terms: Microalgae*
  3. The influence of light intensity and photoperiod on the growth and lipid content of microalgae Nannochloropsis sp
    Wahidin S, Idris A, Shaleh SR
    Bioresour Technol, 2013 Feb;129:7-11.
    PMID: 23232218 DOI: 10.1016/j.biortech.2012.11.032
    Illumination factors such as length of photoperiod and intensity can affect growth of microalgae and lipid content. In order to optimize microalgal growth in mass culture system and lipid content, the effects of light intensity and photoperiod cycle on the growth of the marine microalgae, Nannochloropsis sp. were studied in batch culture. Nannochloropsis sp. was grown aseptically for 9 days at three different light intensities (50, 100 and 200 μmol m(-2) s(-1)) and three different photoperiod cycles (24:0, 18:06 and 12:12 h light:dark) at 23 °C cultivation temperature. Under the light intensity of 100 μmol m(-2) s(-1) and photoperiod of 18 h light: 6 h dark cycle, Nannochloropsis sp. was found to grow favorably with a maximum cell concentration of 6.5×10(7) cells mL(-1), which corresponds to the growth rate of 0.339 d(-1) after 8 day cultivation and the lipid content was found to be 31.3%.
    Matched MeSH terms: Microalgae/physiology*; Microalgae/radiation effects*
  4. Ionic liquid as a promising biobased green solvent in combination with microwave irradiation for direct biodiesel production
    Wahidin S, Idris A, Shaleh SR
    Bioresour Technol, 2016 Apr;206:150-4.
    PMID: 26851899 DOI: 10.1016/j.biortech.2016.01.084
    The wet biomass microalgae of Nannochloropsis sp. was converted to biodiesel using direct transesterification (DT) by microwave technique and ionic liquid (IL) as the green solvent. Three different ionic liquids; 1-butyl-3-metyhlimidazolium chloride ([BMIM][Cl], 1-ethyl-3-methylimmidazolium methyl sulphate [EMIM][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][CF3SO3]) and organic solvents (hexane and methanol) were used as co-solvents under microwave irradiation and their performances in terms of percentage disruption, cell walls ruptured and biodiesel yields were compared at different reaction times (5, 10 and 15 min). [EMIM][MeSO4] showed highest percentage cell disruption (99.73%) and biodiesel yield (36.79% per dried biomass) after 15 min of simultaneous reaction. The results demonstrated that simultaneous extraction-transesterification using ILs and microwave irradiation is a potential alternative method for biodiesel production.
    Matched MeSH terms: Microalgae/chemistry*
  5. Mechanistic behaviour of Chlorella vulgaris biofilm formation onto waste organic solid support used to treat palm kernel expeller in the recent Anthropocene
    Rawindran H, Syed R, Alangari A, Khoo KS, Lim JW, Sahrin NT, et al.
    Environ Res, 2023 Apr 01;222:115352.
    PMID: 36716802 DOI: 10.1016/j.envres.2023.115352
    The capacity to maximize the proliferation of microalgal cells by means of topologically textured organic solid surfaces under various pH gave rise to the fundamental biophysical analysis of cell-surface attachment in this study. The substrate used in analysis was palm kernel expeller (PKE) in which the microalgal cells had adhered onto its surface. The findings elucidated the relevance of surface properties in terms of surface wettability and surface energy in relation to the attached microalgal growth with pH as the limiting factor. The increase in hydrophobicity of PKE-microalgae attachment was able to facilitate the formation of biofilm better. The pH 5 and pH 11 were found to be the conditions with highest and lowest microalgal growths, respectively, which were in tandem with the highest contact angle value at pH 5 and conversely for pH 11. The work of attachment (Wcs) had supported the derived model with positive values being attained for all the pH conditions, corroborating the thermodynamic feasibility. Finally, this study had unveiled the mechanism of microalgal attachment onto the surface of PKE using the aid of extracellular polymeric surfaces (EPS) from microalgae. Also, the hydrophobic nature of PKE enabled excellent attachment alongside with nutrients for microalgae to grow and from layer-by-layer (LbL) assembly. This assembly was then isolated using organosolv method by means of biphasic solvents, namely, methanol and chloroform, to induce detachment.
    Matched MeSH terms: Microalgae*
  6. Production of lipids containing high levels of docosahexaenoic acid by a newly isolated microalga, Aurantiochytrium sp. KRS101
    Hong WK, Rairakhwada D, Seo PS, Park SY, Hur BK, Kim CH, et al.
    Appl Biochem Biotechnol, 2011 Aug;164(8):1468-80.
    PMID: 21424706 DOI: 10.1007/s12010-011-9227-x
    In the present study, a novel oleaginous Thraustochytrid containing a high content of docosahexaenoic acid (DHA) was isolated from a mangrove ecosystem in Malaysia. The strain identified as an Aurantiochytrium sp. by 18S rRNA sequencing and named KRS101 used various carbon and nitrogen sources, indicating metabolic versatility. Optimal culture conditions, thus maximizing cell growth, and high levels of lipid and DHA production, were attained using glucose (60 g l⁻¹) as carbon source, corn steep solid (10 g l⁻¹) as nitrogen source, and sea salt (15 g l⁻¹). The highest biomass, lipid, and DHA production of KRS101 upon fed-batch fermentation were 50.2 g l⁻¹ (16.7 g l⁻¹ day⁻¹), 21.8 g l⁻¹ (44% DCW), and 8.8 g l⁻¹ (40% TFA), respectively. Similar values were obtained when a cheap substrate like molasses, rather than glucose, was used as the carbon source (DCW of 52.44 g l⁻¹, lipid and DHA levels of 20.2 and 8.83 g l⁻¹, respectively), indicating that production of microbial oils containing high levels of DHA can be produced economically when the novel strain is used.
    Matched MeSH terms: Microalgae/genetics; Microalgae/isolation & purification; Microalgae/metabolism*
  7. Microalgal remediation and valorisation of polluted wastewaters for zero-carbon circular bioeconomy
    Goveas LC, Nayak S, Vinayagam R, Loke Show P, Selvaraj R
    Bioresour Technol, 2022 Dec;365:128169.
    PMID: 36283661 DOI: 10.1016/j.biortech.2022.128169
    Overexploitation of natural resources to meet human needs has considerably impacted CO2 emissions, contributing to global warming and severe climatic change. This review furnishes an understanding of the sources, brutality, and effects of CO2 emissions and compelling requirements for metamorphosis from a linear to a circular bioeconomy. A detailed emphasis on microalgae, its types, properties, and cultivation are explained with significance in attaining a zero-carbon circular bioeconomy. Microalgal treatment of a variety of wastewaters with the conversion of generated biomass into value-added products such as bio-energy and pharmaceuticals, along with agricultural products is elaborated. Challenges encountered in large-scale implementation of microalgal technologies for low-carbon circular bioeconomy are discussed along with solutions and future perceptions. Emphasis on the suitability of microalgae in wastewater treatment and its conversion into alternate low-carbon footprint bio-energies and value-added products enforcing a zero-carbon circular bioeconomy is the major focus of this review.
    Matched MeSH terms: Microalgae*
  8. Novel sequential flow baffled microalgal-bacterial photobioreactor for enhancing nitrogen assimilation into microalgal biomass whilst bioremediating nutrient-rich wastewater simultaneously
    Leong WH, Lim JW, Lam MK, Lam SM, Sin JC, Samson A
    J Hazard Mater, 2021 05 05;409:124455.
    PMID: 33168319 DOI: 10.1016/j.jhazmat.2020.124455
    A novel sequential flow baffled microalgal-bacterial (SFB-AlgalBac) photobioreactor was designed to cater for the synergistic interactions between microalgal and bacterial consortia to enhance nitrogen assimilation into microalgal biomass from nutrient-rich wastewater medium. The performance of the SFB-AlgalBac photobioreactor was found to be optimum at the influent flow rate of 5.0 L/d, equivalent to 20 days of hydraulic retention time (HRT). The highest microalgal nitrogen assimilation rate (0.0271 /d) and biomass productivity (1350 mg/d) were recorded amidst this flow rate. Further increase to the 10.0 L/d flow rate reduced the photobioreactor performance, as evidenced by a reduction in microalgal biomass productivity (>10%). The microalgal biomass per unit of nitrogen assimilated values were attained at 16.69 mg/mg for the 5.0 L/d flow rate as opposed to 7.73 mg/mg for the 10.0 L/d flow rate, despite both having comparable specific growth rates. Also, the prior influent treatment by activated sludge was found to exude extracellular polymeric substances which significantly improved the microalgal biomass settleability up to 37%. The employment of SFB-AlgalBac photobioreactor is anticipated could exploit the low-cost nitrogen sources from nutrient-rich wastewaters via bioconversion into valuable microalgal biomass while fulfilling the requirements of sustainable wastewater treatment technologies.
    Matched MeSH terms: Microalgae*
  9. Screening factors influencing the production of astaxanthin from freshwater and marine microalgae
    Binti Ibnu Rasid EN, Mohamad SE, Jamaluddin H, Salleh MM
    Appl Biochem Biotechnol, 2014 Feb;172(4):2160-74.
    PMID: 24338298 DOI: 10.1007/s12010-013-0644-x
    Astaxanthin, a carotenoid pigment found in several aquatic organisms, is responsible for the red colour of salmon, trout and crustaceans. In this study, astaxanthin production from freshwater microalga Chlorella sorokiniana and marine microalga Tetraselmis sp. was investigated. Cell growth and astaxanthin production were determined spectrophotometrically at 620 and 480 nm, respectively. Astaxanthin was extracted using acetone and measured subsequent to biomass removal. Aerated conditions favoured astaxanthin production in C. sorokiniana, whereas Tetraselmis sp. was best cultured under unaerated conditions. C. sorokiniana produced more astaxanthin with the highest yield reached at 7.83 mg/l in 6.0 mM in nitrate containing medium compared to Tetraselmis sp. which recorded the highest yield of only 1.96 mg/l in 1.5 mM nitrate containing medium. Production in C. sorokiniana started at the early exponential phase, indicating that astaxanthin may be a growth-associated product in this microalga. Further optimization of astaxanthin production was performed using C. sorokiniana through a 2(3) full factorial experimental design, and a yield of 8.39 mg/l was achieved. Overall, the study has shown that both microalgae are capable of producing astaxanthin. Additionally, this research has highlighted C. sorokiniana as a potential astaxanthin producer that could serve as a natural astaxanthin source in the current market.
    Matched MeSH terms: Microalgae/metabolism*
  10. Fulltext Latest development in microalgae-biofuel production with nano-additives
    Hossain N, Mahlia TMI, Saidur R
    Biotechnol Biofuels, 2019;12:125.
    PMID: 31139255 DOI: 10.1186/s13068-019-1465-0
    Background: Microalgae have been experimented as a potential feedstock for biofuel generation in current era owing to its' rich energy content, inflated growth rate, inexpensive culture approaches, the notable capacity of CO2 fixation, and O2 addition to the environment. Currently, research is ongoing towards the advancement of microalgal-biofuel technologies. The nano-additive application has been appeared as a prominent innovation to meet this phenomenon.

    Main text: The main objective of this study was to delineate the synergistic impact of microalgal biofuel integrated with nano-additive applications. Numerous nano-additives such as nano-fibres, nano-particles, nano-tubes, nano-sheets, nano-droplets, and other nano-structures' applications have been reviewed in this study to facilitate microalgae growth to biofuel utilization. The present paper was intended to comprehensively review the nano-particles preparing techniques for microalgae cultivation and harvesting, biofuel extraction, and application of microalgae-biofuel nano-particles blends. Prospects of solid nano-additives and nano-fluid applications in the future on microalgae production, microalgae biomass conversion to biofuels as well as enhancement of biofuel combustion for revolutionary advancement in biofuel technology have been demonstrated elaborately by this review. This study also highlighted the potential biofuels from microalgae, numerous technologies, and conversion processes. Along with that, the study recounted suitability of potential microalgae candidates with an integrated design generating value-added co-products besides biofuel production.

    Conclusions: Nano-additive applications at different stages from microalgae culture to end-product utilization presented strong possibility in mercantile approach as well as positive impact on the environment along with valuable co-products generation into the near future.

    Matched MeSH terms: Microalgae
  11. Acute oral toxicity study on Wistar rats fed microalgal protein hydrolysates from Bellerochea malleus
    Barkia I, Ketata Bouaziz H, Sellami Boudawara T, Aleya L, Gargouri AF, Saari N
    Environ Sci Pollut Res Int, 2020 Jun;27(16):19087-19094.
    PMID: 30612348 DOI: 10.1007/s11356-018-4007-6
    Protein hydrolysates and bioactive peptides from various protein sources have demonstrated their effectiveness for the prevention of illness and the improvement of symptoms from several diseases. In particular, the use of microalgae to generate bioactive peptides has received a growing interest because of their potential to be cultivated on non-arable land and high nutritional value. However, scant research is available on the toxicity of peptide-based preparations. The present study aims to evaluate the toxicity of microalgal protein hydrolysates (MPH) from one marine species of microalgae (Bellerochea malleus) to determine the feasibility of their use for functional food applications. Results showed that the oral administration of MPH at three doses (D1, 100 mg kg-1 BW; D2, 400 mg kg-1 BW; and D3, 2000 mg kg-1 BW) to male Wistar rats did not induce any adverse effects or mortality up to13 days of treatment. Data analysis of relative organ weights and biochemical and hematological parameters did not show any significant differences between control and treated groups at the three doses investigated. Data from histopathological observations did not reveal any signs of major toxicity at the doses D1 and D2. However, mild signs of inflammation and necrosis were observed in the kidney of rats fed MPH at D3. All together, these results reveal the overall safety of MPH and provide new evidence for advocating their use for functional food or nutraceutical applications.
    Matched MeSH terms: Microalgae*
  12. Single chamber microbial fuel cell (SCMFC) with a cathodic microalgal biofilm: A preliminary assessment of the generation of bioelectricity and biodegradation of real dye textile wastewater
    Logroño W, Pérez M, Urquizo G, Kadier A, Echeverría M, Recalde C, et al.
    Chemosphere, 2017 Mar 01;176:378-388.
    PMID: 28278426 DOI: 10.1016/j.chemosphere.2017.02.099
    An air exposed single-chamber microbial fuel cell (SCMFC) using microalgal biocathodes was designed. The reactors were tested for the simultaneous biodegradation of real dye textile wastewater (RTW) and the generation of bioelectricity. The results of digital image processing revealed a maximum coverage area on the biocathodes by microalgal cells of 42%. The atmospheric and diffused CO2 could enable good algal growth and its immobilized operation on the cathode electrode. The biocathode-SCMFCs outperformed an open circuit voltage (OCV), which was 18%-43% higher than the control. Furthermore, the maximum volumetric power density achieved was 123.2 ± 27.5 mW m(-3). The system was suitable for the treatment of RTW and the removal/decrease of COD, colour and heavy metals. High removal efficiencies were observed in the SCMFCs for Zn (98%) and COD (92-98%), but the removal efficiencies were considerably lower for Cr (54-80%). We observed that this single chamber MFC simplifies a double chamber system. The bioelectrochemical performance was relatively low, but the treatment capacity of the system seems encouraging in contrast to previous studies. A proof-of-concept experiment demonstrated that the microalgal biocathode could operate in air exposed conditions, seems to be a promising alternative to a Pt cathode and is an efficient and cost-effective approach to improve the performance of single chamber MFCs.
    Matched MeSH terms: Microalgae
  13. Fulltext The Effects of Microalgae as Live Food for Brachionus plicatilis (Rotifer) in Intensive Culture System
    Rahman ARA, Cob ZC, Jamari Z, Mohamed AM, Toda T, Ross OH
    Trop Life Sci Res, 2018 Mar;29(1):127-138.
    PMID: 29644020 MyJurnal DOI: 10.21315/tlsr2018.29.1.9
    Brachionus plicatilis is used to feed fish and crustacean larvae in the aquaculture industry. It is well established that the type of microalgae may influence rotifer production. This experiment was conducted to determine the effect of five different locally available microalgae species at Fisheries Research Institute (FRI), Kampung Pulau Sayak, Kedah, Malaysia on the instantaneous growth rate (μ) of rotifer. Nannochloris sp., Tetraselmis sp., Isochrysis sp., Chlorella sp., and Nannochloropsis sp. were used as feed at different algae densities (0.1, 0.3, 0.7 and 1.5 × 106 cells/ml) and culture volumes (20, 70 and 210 ml). At algae densities ranging from 0.3 to 1.5 × 106 cells/ml, an average μ value of more than 0.90 per day were recorded for all algae species. However, at density of 0.1 × 106 cells/ml, only Tetraselmis sp. resulted in the significantly highest μ value compared with others (p < 0.05). In terms of volume, smaller culture volume of Tetraselmis sp. (20 ml) showed significantly higher μ compared with higher volume (70 and 210 ml cultures).
    Matched MeSH terms: Microalgae
  14. Lipid for biodiesel production from attached growth Chlorella vulgaris biomass cultivating in fluidized bed bioreactor packed with polyurethane foam material
    Mohd-Sahib AA, Lim JW, Lam MK, Uemura Y, Isa MH, Ho CD, et al.
    Bioresour Technol, 2017 Sep;239:127-136.
    PMID: 28501685 DOI: 10.1016/j.biortech.2017.04.118
    The potential to grow attached microalgae Chlorella vulgaris in fluidized bed bioreactor was materialized in this study, targeting to ease the harvesting process prior to biodiesel production. The proposed thermodynamic mechanism and physical property assessment of various support materials verified polyurethane to be suitable material favouring the spontaneous adhesion by microalgae cells. The 1-L bioreactor packed with only 2.4% (v/v) of 1.00-mL polyurethane foam cubes could achieve the highest attached growth microalgae biomass and lipid weights of 812±122 and 376±37mg, respectively, in comparison with other cube sizes. The maturity of attached growth microalgae biomass for harvesting could also be determined from the growth trend of suspended microalgae biomass. Analysis of FAME composition revealed that the harvested microalgae biomass was dominated by C16-C18 (>60%) and mixture of saturated and mono-unsaturated fatty acids (>65%), satiating the biodiesel standard with adequate cold flow property and oxidative stability.
    Matched MeSH terms: Microalgae
  15. Evaluation of hepatoprotective and antioxidant activity of astaxanthin and astaxanthin esters from microalga-Haematococcus pluvialis
    Rao AR, Sarada R, Shylaja MD, Ravishankar GA
    J Food Sci Technol, 2015 Oct;52(10):6703-10.
    PMID: 26396419 DOI: 10.1007/s13197-015-1775-6
    Effect of isolated astaxanthin (ASX) and astaxanthin esters (ASXEs) from green microalga-Haematococcus pluvialis on hepatotoxicity and antioxidant activity against carbon tetrachloride (CCl4) induced toxicity in rats was compared with synthetic astaxanthin (SASX). ASX, ASXEs, and SASX, all dissolved in olive oil, fed to rats with 100 and 250 μg/kg b.w for 14 days. They were evaluated for their hepatoprotective and antioxidant activity by measuring appropriate enzymes. Among the treated groups, the SGPT, SGOT and ALP levels were decreased by 2, 2.4, and 1.5 fold in ASXEs treated group at 250 μg/Kg b.w. when compared to toxin group. Further, antioxidant enzymes catalase, glutathione, superoxide dismutase and lipid peroxidase levels were estimated in treated groups, their levels were reduced by 30-50 % in the toxin group, however these levels restored by 136.95 and 238.48 % in ASXEs treated group at 250 μg/kg. The lipid peroxidation was restored by 5.2 and 2.8 fold in ASXEs and ASX treated groups at 250 μg/kg. The total protein, albumin and bilirubin contents were decreased in toxin group, whereas normalized in ASXEs treated group. These results indicates that ASX and ASXEs have better hepatoprotection and antioxidant activity, therefore can be used in pharmaceutical and nutraceutical applications and also extended to use as food colorant.
    Matched MeSH terms: Microalgae
  16. Fulltext Improved Nylon 6,6 Nanofiber Membrane in A Tilted Panel Filtration System for Fouling Control in Microalgae Harvesting
    Mat Nawi NI, Abd Halim NS, Lee LC, Wirzal MDH, Bilad MR, Nordin NAH, et al.
    Polymers (Basel), 2020 Jan 21;12(2).
    PMID: 31973178 DOI: 10.3390/polym12020252
    The competitiveness of algae as biofuel feedstock leads to the growth of membrane filtration as one of promising technologies for algae harvesting. Nanofiber membrane (NFM) was found to be efficient for microalgae harvesting via membrane filtration, but it is highly limited by its weak mechanical strength. The main objective of this study is to enhance the applicability of nylon 6,6 NFM for microalgae filtration by optimizing the operational parameters and applying solvent vapor treatment to improve its mechanical strength. The relaxation period and filtration cycle could be optimized to improve the hydraulic performance. For a cycle of 5 min., relaxation period of ≤2 min shows the highest steady-state permeability of 365 ± 14.14 L m-2 h-1 bar-1, while for 10 min cycle, 3 min. of relaxation period was found optimum that yields permeability of 402 ± 34.47 L m-2 h-1 bar-1. The treated nylon 6,6 NFM was also used to study the effect of aeration rate. It is confirmed that the aeration rate enhances the steady-state performance for both intermittent and continuous mode of aeration. Remarkably, intermittent aeration shows 7% better permeability than the full aeration for all tested condition, which is beneficial for reducing the total energy consumption.
    Matched MeSH terms: Microalgae
  17. Technical difficulties and solutions of direct transesterification process of microbial oil for biodiesel synthesis
    Yousuf A, Khan MR, Islam MA, Wahid ZA, Pirozzi D
    Biotechnol Lett, 2017 Jan;39(1):13-23.
    PMID: 27659031 DOI: 10.1007/s10529-016-2217-x
    Microbial oils are considered as alternative to vegetable oils or animal fats as biodiesel feedstock. Microalgae and oleaginous yeast are the main candidates of microbial oil producers' community. However, biodiesel synthesis from these sources is associated with high cost and process complexity. The traditional transesterification method includes several steps such as biomass drying, cell disruption, oil extraction and solvent recovery. Therefore, direct transesterification or in situ transesterification, which combines all the steps in a single reactor, has been suggested to make the process cost effective. Nevertheless, the process is not applicable for large-scale biodiesel production having some difficulties such as high water content of biomass that makes the reaction rate slower and hurdles of cell disruption makes the efficiency of oil extraction lower. Additionally, it requires high heating energy in the solvent extraction and recovery stage. To resolve these difficulties, this review suggests the application of antimicrobial peptides and high electric fields to foster the microbial cell wall disruption.
    Matched MeSH terms: Microalgae/drug effects; Microalgae/genetics; Microalgae/metabolism*
  18. A metabolomic approach to investigate effects of ocean acidification on a polar microalga Chlorella sp
    Tan YH, Lim PE, Beardall J, Poong SW, Phang SM
    Aquat Toxicol, 2019 Dec;217:105349.
    PMID: 31734626 DOI: 10.1016/j.aquatox.2019.105349
    Ocean acidification, due to increased levels of anthropogenic carbon dioxide, is known to affect the physiology and growth of marine phytoplankton, especially in polar regions. However, the effect of acidification or carbonation on cellular metabolism in polar marine phytoplankton still remains an open question. There is some evidence that small chlorophytes may benefit more than other taxa of phytoplankton. To understand further how green polar picoplankton could acclimate to high oceanic CO2, studies were conducted on an Antarctic Chlorella sp. Chlorella sp. maintained its growth rate (∼0.180 d-1), photosynthetic quantum yield (Fv/Fm = ∼0.69) and chlorophyll a (0.145 fg cell-1) and carotenoid (0.06 fg cell-1) contents under high CO2, while maximum rates of electron transport decreased and non-photochemical quenching increased under elevated CO2. GCMS-based metabolomic analysis reveal that this polar Chlorella strain modulated the levels of metabolites associated with energy, amino acid, fatty acid and carbohydrate production, which could favour its survival in an increasingly acidified ocean.
    Matched MeSH terms: Microalgae/drug effects; Microalgae/metabolism*
  19. Fulltext Evaluation of selected tropical marine microalgal cultures for use in biophotovoltaic platforms
    Tay ZH, Ng FL, Thong CH, Lee CW, Gnana Kumar G, Al-Sehemi AG, et al.
    Appl Microbiol Biotechnol, 2024 Dec;108(1):1-14.
    PMID: 38194143 DOI: 10.1007/s00253-023-12951-0
    In this study, the bioelectrical power generation potential of four tropical marine microalgal strains native to Malaysia was investigated using BPV platforms. Chlorella UMACC 258 produced the highest power density (0.108 mW m-2), followed by Halamphora subtropica UMACC 370 (0.090 mW m-2), Synechococcus UMACC 371 (0.065 mW m-2) and Parachlorella UMACC 245 (0.017 mW m-2). The chlorophyll-a (chl-a) content was examined to have a linear positive relationship with the power density (p 
    Matched MeSH terms: Microalgae*
  20. Investigation on the enhancement of crack restoration properties in cement incorporated with Arthrospira platensis cultured in modified medium
    M KS, Alengaram UJ, Ibrahim S, Vello V, Phang SM
    Environ Sci Pollut Res Int, 2024 Apr;31(17):25538-25558.
    PMID: 38478311 DOI: 10.1007/s11356-024-32784-2
    This study investigated the potential use of microalgae as partial cement replacement to heal cracks in cement mortar. Microbially induced calcite (CaCO3) precipitation (MICP) from Arthrospira platensis (A. platensis) (UMACC162) was utilised for crack-healing applications. Microalgae was cultivated in Kosaric Media (KM) together with filtered cement water (FCW), and used as a cement replacement material. The microalgal species was further evaluated for its capacity and adaptability towards large-scale culturing. The results showed that A. platensis could adapt and survive in cement water solution and cement mortar, suggesting the potential for self-healing in cement mortar. Further, the cultured species grown in both conditions (KM and KM & FCW) were harvested and incorporated into the cement mortar as a partial cement replacement material at different levels of 5%, 10%, 20%, and 30% of cement weight. The cement mortars partially replaced with microalgae were cured in water for 28 days. Pre-cracks were induced in the cured mortar with the 75% of their ultimate load. It took just 14 days for the microalgae-incorporated mortar to heal the cracks. The specimens with microalgae cultured in FCW showed a better performance and recovered 59% of their strength, with a maximum healed crack width of 0.7 mm. In terms of water tightness and porosity, they are comparable to the control mortar. The compressive strength measurements indicated the formation of calcite aggregate (crystal) that sealed the surface cracks, which was confirmed by a microstructural analysis. The results also demonstrate that the incorporation of microalgae into cement produced a self-healing effect, providing a new direction for crack healing. Additionally, the investigation indicated that replacing cement with microalgae reduced CO2 emissions by as much as 30%, with a substitution of 30% of microalgae. Exploring microalgae as a cement replacement could reduce carbon emissions and improve the state of the environment.
    Matched MeSH terms: Microalgae*
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