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Fulltext Enhancement of Biomass and Calcium Carbonate Biomineralization of Chlorellavulgaris through Plackett-Burman Screening and Box-Behnken Optimization Approach

Chin ZW, Arumugam K, Ashari SE, Faizal Wong FW, Tan JS, Ariff AB, et al.

Molecules, 2020 Jul 28;25(15).
PMID: 32731437 DOI: 10.3390/molecules25153416

The biosynthesis of calcium carbonate (CaCO3) minerals through a metabolic process known as microbially induced calcium carbonate precipitation (MICP) between diverse microorganisms, and organic/inorganic compounds within their immediate microenvironment, gives rise to a cementitious biomaterial that may emerge as a promissory alternative to conventional cement. Among photosynthetic microalgae, Chlorella vulgaris has been identified as one of the species capable of undergoing such activity in nature. In this study, response surface technique was employed to ascertain the optimum condition for the enhancement of biomass and CaCO3 precipitation of C. vulgaris when cultured in Blue-Green (BG)-11 aquaculture medium. Preliminary screening via Plackett-Burman Design showed that sodium nitrate (NaNO3), sodium acetate, and urea have a significant effect on both target responses (p < 0.05). Further refinement was conducted using Box-Behnken Design based on these three factors. The highest production of 1.517 g/L C. vulgaris biomass and 1.143 g/L of CaCO3 precipitates was achieved with a final recipe comprising of 8.74 mM of NaNO3, 61.40 mM of sodium acetate and 0.143 g/L of urea, respectively. Moreover, polymorphism analyses on the collected minerals through morphological examination via scanning electron microscopy and crystallographic elucidation by X-ray diffraction indicated to predominantly calcite crystalline structure.

Matched MeSH terms: Chlorella vulgaris/growth & development*
Intensity of blue LED light: a potential stimulus for biomass and lipid content in fresh water microalgae Chlorella vulgaris

Atta M, Idris A, Bukhari A, Wahidin S

Bioresour Technol, 2013 Nov;148:373-8.
PMID: 24063820 DOI: 10.1016/j.biortech.2013.08.162

Light quality and the intensity are key factors which render microalgae as a potential source of biodiesel. In this study the effects of various intensities of blue light and its photoperiods on the growth and lipid content of Chlorella vulgaris were investigated by using LED (Light Emitting Diode) in batch culture. C. vulgaris was grown for 13 days at three different light intensities (100, 200 and 300 μmol m(-2)s(-1)). Effect of three different light and dark regimes (12:12, 16:08 and 24:00 h Light:Dark) were investigated for each light intensity at 25°C culture temperature. Maximum lipid content (23.5%) was obtained due to high efficiency and deep penetration of 200 μmol m(-2)s(-1) of blue light (12:12 L:D) with improved specific growth (1.26 d(-1)) within reduced cultivation time of 8 days. White light could produce 20.9% lipid content in 10 days at 16:08 h L:D.

Matched MeSH terms: Chlorella vulgaris/growth & development*
Fulltext Kinetics Growth and Recovery of Valuable Nutrients from Selangor Peat Swamp and Pristine Forest Soils Using Different Extraction Methods as Potential Microalgae Growth Enhancers

Yaacob NS, Ahmad MF, Kawasaki N, Maniyam MN, Abdullah H, Hashim EF, et al.

Molecules, 2021 Jan 27;26(3).
PMID: 33513787 DOI: 10.3390/molecules26030653

Soil extracts are useful nutrients to enhance the growth of microalgae. Therefore, the present study attempts for the use of virgin soils from Peninsular Malaysia as growth enhancer. Soils collected from Raja Musa Forest Reserve (RMFR) and Ayer Hitam Forest Reserve (AHFR) were treated using different extraction methods. The total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and dissolved organic carbon (DOC) concentrations in the autoclave methods were relatively higher than natural extraction with up to 132.0 mg N/L, 10.7 mg P/L, and 2629 mg C/L, respectively for RMFR. The results of TDN, TDP, and DOC suggested that the best extraction methods are autoclaved at 121 °C twice with increasing 87%, 84%, and 95%, respectively. Chlorella vulgaris TRG 4C dominated the growth at 121 °C twice extraction method in the RMRF and AHRF samples, with increasing 54.3% and 14%, respectively. The specific growth rate (µ) of both microalgae were relatively higher, 0.23 d-1 in the Ayer Hitam Soil. This extract served well as a microalgal growth promoter, reducing the cost and the needs for synthetic medium. Mass production of microalgae as aquatic feed will be attempted eventually. The high recovery rate of nutrients has a huge potential to serve as a growth promoter for microalgae.

Matched MeSH terms: Chlorella vulgaris/growth & development
Fulltext Impact of magnetic immobilization on the cell physiology of green unicellular algae Chlorella vulgaris

Taghizadeh SM, Berenjian A, Chew KW, Show PL, Mohd Zaid HF, Ramezani H, et al.

Bioengineered, 2020 12;11(1):141-153.
PMID: 31994978 DOI: 10.1080/21655979.2020.1718477

Cell immobilization on the magnetic nanoparticles (MNPs) and magnetic harvesting is a novel approach for microalgal cells separation. To date, the effect of these nanoparticles on microalgal cells was only studied over a short period of time. More studies are hence needed for a better understanding of the magnetic harvesting proposes or environmental concerns relating to long-term exposure to nanoparticles. In this study, the impact of various concentrations of MNPs on the microalgal cells growth and their metabolic status was investigated over 12 days. More than 60% reduction in mitochondrial activity and pigments (chlorophyll a, chlorophyll b, and carotenoids) content occurred during the first 6 days of exposure to ≥50 µg/mL nanoparticles. However, more than 50% growth inhibitory effect was seen at concentrations higher than 400 µg/mL. Exposure to MNPs gradually induced cellular adaptation and after about 6 days of exposure to stress generating concentrations (˂400 µg/mL) of IONs, microalgae could overcome the imposed damages. This work provides a better understanding regarding the environmental impact of MNPs and appropriate concentrations of these particles for future algal cells magnetic immobilization and harvesting.

Matched MeSH terms: Chlorella vulgaris/growth & development
A brief period of darkness induces changes in fatty acid biosynthesis towards accumulation of saturated fatty acids in Chlorella vulgaris UMT-M1 at stationary growth phase

Cha TS, Yee W, Phua PSP, Loh SH, Aziz A

Biotechnol Lett, 2021 Apr;43(4):803-812.
PMID: 33438120 DOI: 10.1007/s10529-021-03077-2

OBJECTIVE: The effects of a brief (3 days) and prolonged (6 days) period of incubation in darkness and light on the biomass content, lipid content and fatty acid profile in Chlorella vulgaris UMT-M1 were determined.
RESULTS: Three days of incubation in darkness increased saturated fatty acid (SFA) content from 34.0 to 41.4% but decreased monounsaturated fatty acid (MUFA) content from 36.7 to 29.8%. Palmitic acid (C16:0) content was increased from 23.2 to 28.9%, whereas oleic acid (C18:1) content was reduced from 35.4 to 28.8%. Total oil content was slightly decreased from 20.4 to 18.7% after 3 days of darkness, without a significant reduction in biomass compared to 3 days of incubation in light. Biomass and oil content was highest in cultures incubated for 6 days in light, however the stimulatory and inhibitory effects of darkness (or light) on SFA and MUFA content was no longer present at 6 days of incubation.
CONCLUSIONS: Findings from this study suggests that fatty acid composition in C. vulgaris could be modulated to favor either C16:0 or C18:1 by a brief period of either darkness or light incubation, prior to harvesting.

Matched MeSH terms: Chlorella vulgaris/growth & development*
Use of Chlorella vulgaris for bioremediation of textile wastewater

Lim SL, Chu WL, Phang SM

Bioresour Technol, 2010 Oct;101(19):7314-22.
PMID: 20547057 DOI: 10.1016/j.biortech.2010.04.092

The potential application of Chlorella vulgaris UMACC 001 for bioremediation of textile wastewater (TW) was investigated using four batches of cultures in high rate algae ponds (HRAP) containing textile dye (Supranol Red 3BW) or TW. The biomass attained ranged from 0.17 to 2.26 mg chlorophyll a/L while colour removal ranged from 41.8% to 50.0%. There was also reduction of NH(4)-N (44.4-45.1%), PO(4)-P (33.1-33.3%) and COD (38.3-62.3%) in the TW. Supplementation of the TW with nutrients of Bold's Basal Medium (BBM) increased biomass production but did not improve colour removal or reduction of pollutants. The mechanism of colour removal by C. vulgaris is biosorption, in accordance with both the Langmuir and Freundlich models. The HRAP using C. vulgaris offers a good system for the polishing of TW before final discharge.

Matched MeSH terms: Chlorella vulgaris/growth & development
Fulltext Lipid accumulation patterns and role of different fatty acid types towards mitigating salinity fluctuations in Chlorella vulgaris

Teh KY, Loh SH, Aziz A, Takahashi K, Effendy AWM, Cha TS

Sci Rep, 2021 01 11;11(1):438.
PMID: 33432049 DOI: 10.1038/s41598-020-79950-3

Mangrove-dwelling microalgae are well adapted to frequent encounters of salinity fluctuations across their various growth phases but are lesser studied. The current study explored the adaptive changes (in terms of biomass, oil content and fatty acid composition) of mangrove-isolated C. vulgaris UMT-M1 cultured under different salinity levels (5, 10, 15, 20, 30 ppt). The highest total oil content was recorded in cultures at 15 ppt salinity (63.5% of dry weight) with uncompromised biomass productivity, thus highlighting the 'trigger-threshold' for oil accumulation in C. vulgaris UMT-M1. Subsequently, C. vulgaris UMT-M1 was further assessed across different growth phases under 15 ppt. The various short, medium and long-chain fatty acids (particularly C20:0), coupled with a high level of C18:3n3 PUFA reported at early exponential phase represents their physiological importance during rapid cell growth. Accumulation of C18:1 and C18:2 at stationary growth phase across all salinities was seen as cells accumulating substrate for C18:3n3 should the cells anticipate a move from stationary phase into new growth phase. This study sheds some light on the possibility of 'triggered' oil accumulation with uninterrupted growth and the participation of various fatty acid types upon salinity mitigation in a mangrove-dwelling microalgae.

Matched MeSH terms: Chlorella vulgaris/growth & development