Vulgaris Growth Research Articles

Enhancing the biomass production of microalgae by mixotrophic cultivation using virgin coconut oil mill effluent

Skim is a major by-product of the virgin coconut oil (VCO) industry consisting of nutrients and is currently discharged to the environment as waste. Hence, this research aimed to utilize skim as a medium for Botryococcus braunii and Chlorella vulgaris growth. The effect of organic carbon resourced from glucose and glycerol on biomass was also investigated at certain concentrations with intervals 100:0 to 0:100 (%). Results indicated that Botryococcus braunii and Chlorella vulgaris cultivated under 20% VCO mill effluent gave the highest biomass production, which accounts for 1.69 g/L and 5.34 g/L; 89.40% and 86.70% COD reduction efficiency. Whereas, mixotrophic condition showed a positive trend for Botryococcus braunii at 80:20 (glucose:glycerol) with 5.60 g/L biomass production and 97.64% COD removal efficiency. Vice versa, the addition of glucose:glycerol gave an inhibitory impact on Chlorella vulgaris as the biomass production was merely 1.66 g/L with COD efficiency 94.03%.

Comparative Study of Essential Oil Composition, Anti-bacterial And Antioxidant Activities of the Aerial Parts of Thymus vulgaris Grown in Morocco and France

Thymus vulgaris commonly known as thyme is an aromatic medicinal plant belonging to the Lamiaceae family. Two thyme essential oils grown in Morocco and France were investigated in this work. We analyzed their chemical composition and evaluated their antioxidant and antimicrobial effect. The chemical composition of essential oils was determined by gas chromatography/mass spectrometry. They were evaluated for their antibacterial activity against five marine pathogenic strains isolated from fish species identified as: Vibrio anguillarum, Photobacterium damselae subsp damselae, Aeromonas salmonicida, Edwarsiella tarda and Lactococcus garvieae. Then, the minimum inhibitory and bactericidal concentration values were determined. Furthermore, the antioxidant activity of the two essential oils was assessed in vitro by DPPH and ABTS assays. Thyme grown in France exhibited the greatest antibacterial activity against the studied strains in comparison with thyme grown in Morocco. Moreover, it showed the highest scavenging activity against free radicals produced by DPPH and ABTS with a percentage of 68.41% and 99.10% respectively, while thyme (Morocco) scavenged ABTS with 74.85%. The chemical components of the two essential oils revealed by the gas chromatography-mass spectrometry showed that thyme from France was mainly composed by thymol (35.77%), ortho-cymene (17.23%) and γ-terpinene (8.05%), while thyme from Morocco had borneol (31.04%), α-terpineol (15.16%), and carvacrol (7.13%) as the major constituents. These results showed the potential of thyme essential oils to be used in the aquaculture sector as phytobiotics to substitute chemicals and antibiotics weakening fish quality besides threatening the health of fish consumers.

Improvement of Phaseolus vulgaris growth by inoculation with multifunctional native rhizobacteria isolated from rhizospheric soils in Gaza strip- Palestine

Improvement of Phaseolus vulgaris growth by inoculation with multifunctional native rhizobacteria isolated from rhizospheric soils in Gaza strip- Palestine

Tubular photobioreactors illuminated with LEDs to boost microalgal biomass production

This work proposes distinct configurations for tubular photobioreactors (PBRs) illuminated with specific and adequate light wavelength provided by LEDs. The PBRs are characterized by an involute/flat reflective surface around/below a cylindrical borosilicate glass tube that is illuminated by a LEDs panel located above. Reflectors can enlarge the absorber tube's illuminated area, enabling a uniform (spatial and temporal) light distribution across the culture vessel. Additionally, high-energy-efficient LEDs can minimize heat generation and energetic-related costs. Coupling these two factors can result in higher light utilization efficiency and photosynthetic activity. Depending on the reflector design, almost all the light arriving at the collector aperture can be collected and available for microalgal cultivation. Chlorella vulgaris (C. vulgaris) growth was evaluated as a function of the reflector geometry (flat (F), simple double parabola (SP) and traditional double parabola (DP)) and material (anodized aluminum with (MS) and without (R85) protective coating and stainless steel (SS)). C. vulgaris growth as a function of time was found to be in good agreement with the actinometric results, where the parabolic reflectors (SP and DP) made of higher specular reflectance materials (R85 and MS) were the most efficient systems. Conversely, energy-based specific growth rates slightly increased as the photon flux decreased, signaling an energetic efficiency loss due to the low transmissibility of microalgal suspensions. Additional tests using two absorber tubes (spaced between 12.5 and 75.0 mm) over the R85-F reflector were also carried out, showing that the distance of 50.0 mm led to the best compromise between the specific growth rates and biomass productivities per square meter of solar collector. Under these conditions, higher efficiency on the photonic energy usage was attained compared to the single-tube test.

Seed Vigour Tests on seven Cultivars of Phaseolus vulgaris Grown in Chamoli District of Uttarakhand, India

Rajmash (Phaseolus vulgaris L. family; fabaceae) is also known as kidney bean/ French bean. It is an annual plant and cultivated throughout the world for their edible beans. The present study was conducted to investigate the effect of seed vigour by germination test of different cultivars of Phaseolus vulgaris grown in Chamoli district of Uttarakhand. The experimental material constituted a collection of 7 cultivars (Red small, Red big, Grey, Pink, Yellow, Brown, White) of Phaseolus vulgaris. The seed samples of seven cultivars of Phaseolus vulgaris were taken from Joshimath, District Chamoli Garhwal Uttarakhand. Morphological aspects viz; seed weight, seed moisture content, seed density and seed diameter were recorded prior to germination test of Phaseolus vulgaris at Seed Testing Laboratory, Department of Seed Science and Technology, H.N.B Garhwal University. Seeds were sterilized with 0.2% sodium hypochlorite solution for germination test. Two replicates of each variety and 25 seeds in each replicates were kept in petriplates on whatman filter paper. Petriplates were kept in seed germinator at 25 ± 2 °C until final count. The number of normal seedling was counted at the final count, higher the number of normal seedlings greater is the seed vigour. The germination percentage was found 100% in five cultivars, and the other two cultivars showed 96.66% in yellow seeds and 68.33% in Grey cultivar of Phaseolus vulgaris. Brown cultivars represented maximum dry weight of root (0.029 g) while minimum dry weight of root has been recorded in yellow cultivar (0.01353 g). Maximum vigour index were recorded in brown cultivar and minimum was recorded in pink cultivar. The findings from the study indicate that brown cultivar of Phaseolus vulgaris is highly vigours.

Assessment of Selenium and Zinc Enriched Sludge and Duckweed as Slow-Release Micronutrient Biofertilizers for Phaseolus Vulgaris Growth

Assessment of Selenium and Zinc Enriched Sludge and Duckweed as Slow-Release Micronutrient Biofertilizers for Phaseolus Vulgaris Growth

Isolation and characterization of α ‐amylase encoding gene in Bacillus amyloliquefaciens PAS

Amylolytic bacteria are a source of amylase, which is an essential enzyme to support microalgae growth in the bioreactor for microalgae culture. In a previous study, the highest bacterial isolate to hydrolyze amylum (namely PAS) was successfully isolated from Ranu Pani, Indonesia, and it was identified as Bacillus amyloliquefaciens. That bacterial isolate (B. amyloliquefaciens PAS) also has been proven to accelerate Chlorella vulgaris growth in the mini bioreactor. This study aims to detect, isolate, and characterize the PAS’s α‐amylase encoding gene. This study was conducted with DNA extraction, amplification of α‐amylase gene with polymerase chain reaction (PCR) method with the specific primers, DNA sequencing, phylogenetic tree construction, and protein modeling. The result showed that α‐amylase was successfully detected in PAS bacterial isolate. The α‐amylase DNA fragment was obtained 1,468 bp and that translated sequence has an identity of about 98.3% compared to the B. amylolyquefaciens α‐amylase 3BH4 in the Protein Data Bank (PDB). The predicted 3D protein model of the PAS’s α‐amylase encoding gene has amino acid variations that predicted affect the protein’s structure in the small region. This research will be useful for further research to produce recombinant α‐amylase.

Autochthonous plant growth-promoting rhizobacteria enhance Thymus vulgaris growth in well-watered and drought-stressed conditions

Autochthonous plant growth-promoting rhizobacteria enhance Thymus vulgaris growth in well-watered and drought-stressed conditions

C. vulgaris growth batch tests using winery waste digestate as promising raw material for biodiesel and stearin production.

The recovery of high added value compound from waste stream is fundamental to keep biotechnological processes sustainable. In this study, anaerobic digestion of two highly produced organic waste was integrated with microalgae-based processes both to treat liquid digestate and recover high value compounds. Chlorella vulgaris growth was assessed for lipids accumulation and subsequent recovery, using two types of digestate: organic waste and sewage sludge digestate (DIG-OFMSW) and wine lees digestate (DIG-WL). Growth tests were carried out in batch mode and results showed a slightly higher final biomass concentration from DIG-WL (1.36±0.09gl-1) compared to DIG-OFMSW (1.05±0.13gl-1) and a clearly different lipids accumulation yield (28.86±0.05% in DIG-WL compared to 6.1±0.2% of DIG-OFMSW, on total solids). Lipid characterization showed a high oleic acid accumulation (69.52±0.50%w/w in DIG-WL) that positively influence biodiesel properties and a low linolenic acids content (below 0.30%w/w) that comply with European law EN14214 for biodiesel (linolenic acid content lower than 12%w/w). In addition, due to the high concentration of palmitic and stearic acids detected at the end of test, this oil can be used as new substrate to produce stearin, normally produced from palm oil.

Dynamic modelling of microalgae growth under micro-aeration conditions

Microalgae cultivation is a critical prerequisite of biomass and biofuels production, which is conductive to the reduction of fossil energy consumptions, but there are the hydrodynamic challenges. This study proposed a dynamic modelling of microalgae growth using experimental and computational fluid dynamics (CFD) methods. Photosynthesis performances of unicellular microalgae in photobioreactors (PBRs) were investigated. In a regions-dividing airlift PBR-B, flow field and cell-cycle progression of Chlorella vulgaris were studied. It demonstrated adverse effects of the Karman Vortex Street on microalgae exponential growth. High-levels biomass productivity in flow stagnate region emerges. In a PBR-O, cell density and fluorescence intensity of Chlorella vulgaris were elevated by 2.62 % and 46.69 % in the 9th day of cultivation. Therefore, Chlorella vulgaris growth profiles were predicted using this mathematical modelling successfully. It benefits for the retrofits of commercial shear-sensitivity microalgae culture that require aeration in bio-energy industry.

Regulation of carbon source metabolism in mixotrophic microalgae cultivation in response to light intensity variation

Microalgae are one of the promising sources for renewable energy production, and the light intensity variation can affect the biofuel generation and carbon assimilation of mixotrophic microalgae. To reveal the response of carbon assimilation to light intensity, the effect of light intensity on the carbon source metabolism of Chlorella vulgaris under mixotrophic cultivation was investigated in this study. Moreover, the optimal carbon source composition for mixotrophic microalgae cultivation was evaluated using bicarbonate (HCO3−) and carbonate (CO32−) as inorganic carbon sources, and glucose and acetate as organic carbon sources. The optimal light intensity for Chlorella vulgaris growth was at the range of 8000–12000 lux. For the accumulation of biochemical components, low light intensity was beneficial to protein accumulation, and high light intensity was advantageous for carbohydrate and lipid accumulation. With HCO3− and glucose, the maximum lipid content reached 37.0% at a light intensity of 12000 lux. The citrate synthase activity was negatively correlated with light intensity, showing an opposite trend to biomass production. High light intensity had a positive impact on Rubisco expression, which promoted the microalgae growth and carbon fixing. The energy produced by heterotrophic metabolic activities increased at low light intensity, and the enhancement of biomass production with high light intensity was mainly caused by the improved photoreaction efficiency during the mixotrophic cultivation.

Feasibility of the Hybrid Use of Chlorella vulgaris Culture with the Conventional Biological Treatment in Urban Wastewater Treatment Plants

Currently, most wastewater treatment plants do not meet the legal requirements, especially regarding phosphorus and nitrogen contents. In this work, real primary urban wastewater (P-UW) was used as culture medium for the growth of Chlorella vulgaris. Experiments were carried out in batch photobioreactors at laboratory scale. To determine the maximum nutrient removal levels and the optimal pH value for C. vulgaris growth, the following pH values were studied: 5, 6, 7, 8, 9, 10, and 11. Additionally, two control experiments were conducted using UW and tap water at the same conditions but without microalgae inoculation. The operational conditions were agitation rate = 200 rpm, T = 25 °C, aeration rate = 0.5 L/min, and continuous light with illumination intensity = 359 µE m−2 s−1. Significant higher growth was obtained at pH = 7. The direct use of C. vulgaris for P-UW treatment demonstrated high removal percentages of organic (COD and BOD5 removal = 63.4% and 92.3%, respectively) and inorganic compounds (inorganic carbon removal = 99.6%). The final biomass was characterized by an accumulation of high energetic compounds, mainly carbohydrates, which ranged between 63.3% (pH = 5) and 82.8% (pH = 11) and represent a source of biofuels. These new achievements open up the possibility of new horizons in urban wastewater treatment.

BOD and COD removal in vinasses from sugarcane alcoholic distillation by Chlorella vulgaris: Environmental evaluation

Fermentation of sugarcane-derived liquors for ethanol production produces a liquid waste called vinasse, which is highly contaminant and constitutes a serious ecological problem. Therefore, to reduce this liquid waste’s contamination potential, vinasses from the alcoholic distillation were used as a growth medium for microalgae species like Chlorella vulgaris, evaluating their possible environmental advantages and industrial uses. Reductions in COD and BOD of up to 49% and 70% respectively, were observed, coupled with a maximum algal biomass production of 10.50 ± 0.92 g/L. Also, after fermentation, the human ingestion toxicity potential, terrestrial toxicity potential, and photochemical oxidation potential were reduced by 85%, 83%, and 93% respectively. These results contribute to the understanding of C. vulgaris growth using vinasses as a culture medium under strict heterotrophic conditions and the use of microalgal biomass to reduce the environmental burden caused by vinasses.

Cultivation of Chlorella vulgaris on dairy waste using vision imaging for biomass growth monitoring

Continuous automation of conventional industrial operations with smart technology have drawn significant attention. Firstly, the study investigates on optimizing the proportion of industrial biscuit processing waste powder, (B) substituted into BG-11 as a source of cultivation medium for the growth of C. vulgaris. Various percentages of industrial biscuit processing waste powder, (B) were substituted in the inorganic medium to analyse the algal growth and biochemical composition. The use of 40B combination was found to yield highest biomass concentration (4.11 g/L), lipid (260.44 mg/g), protein (263.93 mg/g), and carbohydrate (418.99 mg/g) content compared with all the other culture ratio combination. Secondly, the exploitation of colour acquisition was performed onto C. vulgaris growth phases, and a novel photo-to-biomass concentration estimation was conducted via image processing for three different colour model pixels. Based on linear regression analysis the red, green, blue (RGB) colour model can interpret its colour variance precisely.

Response of Sugar Beet (Beta vulgaris L.) Growth, Yield and Yield Components to Compost and Phosphorus Fertilizers

Sugar beet is one of the sugar crops which widely grown in different regions of the world due to its advantages over Sugarcane. Several studies were conducted in Sudan to assess its adaptation and economic value. However, the aim of this experiment was to study the effect of application of compost and different levels of phosphorus fertilizer and their combination on Sugar beet (Beta vulgaris) growth attributes, yield and yield components. The study was conducted during the winter season 2018 –2019 at the farm of the College of Agriculture, University of Bahri, Alkadaro-Khartoum State, Sudan. The experiment was arranged in Randomized Complete Block Design (RCBD) with three replications and six treatments, namely the Compost (5t./ha.), Phosphorous (P2O5) (88kg./ha.), P2O5 (176 kg./ha.), Compost (5t./ha.)+P2O5 (88kg./ha.), Compost (5t./ha.)+ P2O5 (176Kg./ha.) and the Control (C) respectively. All cultural practices were carried out timely according to the recommendations of the Agricultural Research Centre in Sudan. Then the data pertaining the following agronomic traits were recorded, the leaf number; leaf dry weight (g), leaf area index (LAI) (cm), root diameter (RD) (cm) and root fresh weight (RFW) (g). The results of statistical analysis revealed the application of compost in combination with phosphorus displayed significant increase at 5% level for the leaf number (22.75), leaf area index (5.23), leaf dry weight(36.78), root diameter(69.67) and root fresh weight (422.68), followed by the application of compost alone compared to the control and other treatments. The study concludes that the combination of compost and mineral fertilizer (P2O5) proved to increase all Sugar beet growth and yield parameters.

Characterization of alginate extracted from Sargassum latifolium and its use in Chlorella vulgaris growth promotion and riboflavin drug delivery

Alginates derived from macroalgae have been widely used in a variety of applications due to their stability, biodegradability and biocompatibility. Alginate was extracted from Egyptian Sargassum latifolium thallus yielding 17.5% w/w. The chemical composition of S. latifolium is rich in total sugars (41.08%) and uronic acids (47.4%); while, proteins, lipids and sulfates contents are 4.61, 1.13 and 0.09%, respectively. NMR, FTIR and TGA analyses were also performed. Crystallinity index (0.334) indicates alginate semicrystalline nature. Sodium alginate hydrolysate was evaluated as Chlorella vulgaris growth promoter. The highest stimulation (0.7 g/L biomass) was achieved by using 0.3 g/L alginate hydrolysate supplementation. The highest total soluble proteins and total carbohydrates were 179.22 mg/g dry wt and 620.33 mg/g dry wt, respectively. The highest total phenolics content (27.697 mg/g dry wt.), guaiacol peroxidase activity (2.899 µmol min−1 g−1) were recorded also to 0.3 g/L alginate hydrolysate supplementation. Riboflavin-entrapped barium alginate-Arabic gum polymeric matrix (beads) was formulated to achieve 89.15% optimum drug entrapment efficiency (EE%). All formulations exhibited prolonged riboflavin release over 120 min in simulated gastric fluid, followed Higuchi model (R2 = 0.962–0.887) and Korsmeyer–Peppas model with Fickian release (n ranges from 0.204 to 0.3885).

Microalgae-based bioremediation of wastewaters - Influencing parameters and mathematical growth modelling

Microalgae have been increasingly recognized as relevant for bioremediation purposes, particularly for wastewater polishing. The implementation of microalgae systems requires efforts on the development of strategies to achieve a cost-effective process. Kinetic models are essential to understand microalgae growth, and for a large-scale implementation and operation under the desired standards. This work aims to assess the influence of wastewater composition, and selected external factors (temperature and photoperiod) on Chlorella vulgaris growth and bioremediation ability. Kinetic models (Monod, Schnute, Logistic, Richards and Gompertz) were used and critically compared to describe the microalga growth under the different operating conditions. The concentration of nitrate was found to be critical for growth under a controlled pH, regardless the presence of micronutrients. A mixotrophic growth, even under low concentrations of glucose, allowed C. vulgaris to be more resilient to variations in temperature and photoperiod, without affecting the bioremediation effectiveness. The microalga shown a low growth ability in acidic wastewaters with ammonium as a nitrogen source. The Monod, Logistic and Gompertz models perfectly fitted the microalga growth. Final results provide a set of conditions and associated kinetic parameters of relevance for C. vulgaris bioremediation as well as highlights the role of the microalga for wastewater polishing.

Bacterial-algal coupling system for high strength mariculture wastewater treatment: Effect of temperature on nutrient recovery and microalgae cultivation

In the present study, bacterial-algal coupling system, an integration process of acidogenic fermentation and microalgae cultivation was used for high strength mariculture wastewater (HSMW) treatment, resource recovery and low-cost biomass production. The effect of temperature on Chlorella vulgaris (C. vulgaris) cultivation was investigated with culture medium of acidogenic liquid. The results showed that acidogenic liquid could be used as culture medium for C. vulgaris and higher biomass was obtained compared to control. The acidogenic liquid obtained at initial pH of 8 was the most suitable culture medium for C. vulgaris growth due to befitting C/N and considerable volatile fatty acids. Moreover, the optimum temperature for C. vulgaris cultivation was 25 °C and the removal efficiency of chemical oxygen demand (COD) and NH4+-N from acidogenic liquid could reach 94.4% and 68.8%, respectively. The outcome could create an innovative value chain with environmental sustainability and economic feasibility in aquaculture industry.

Chlorella vulgaris phycoremediation at low Cu+2 contents: Proteomic profiling of microalgal metabolism related to fatty acids and CO2 fixation

The aim of this work was to correlate metabolic changes with copper ions (Cu+2) bioremediation by microalgae C. vulgaris 097 CCMA-UFSCar at low Cu+2 content. The metabolic effects include proteome changes related to fatty acid biosynthesis (value-added product) and carbon fixation (climate change mitigation). Cu+2, even at low concentration, showed a significant negative impact on C. vulgaris growth. The microalgal bioremediation reached 100, 74, 38 and 26% for Cu+2 content at 0.1; 0.3; 0.6 and 0.9 mg L−1, respectively. Regarding proteomics, the numbers of proteins reduced (≈37%) from 581 proteins (control) to 369 proteins (0.9 mg of Cu+2 L−1) compared to control. The microalgal CO2 fixation is strictly related to the Calvin cycle, particularly phase 1, in which ribulose bisphosphate carboxylase large chain (RuBisCO) produces two phosphoglycerate molecules from CO2 and ribulose 1,5-bisphosphate. Then, phosphoglycerate can be metabolically reduced into glucose. When compared to control, the RuBisCO was underexpressed (≈50%). Similar changes in proteomic profiling of metabolism-related to fatty acid biosynthesis was observed. Nevertheless, no protein was found for the cultivation at 0.9 mg of Cu+2 L−1. Thus, the analysis of C. vulgaris proteomic data indicated that even at low concentration, Cu+2 lead to drastic metabolic changes.

Flocculation of Chlorella vulgaris with alum and pH adjustment.

Microalgae, a group of photosynthetic microorganisms, are a promising feedstock for biodiesel production, but their biomass retrieval is a challenging task. Flocculation is a feasible method for dewatering and harvesting microalgae biomass. In the current study, the effect of alum flocculation on Chlorella vulgaris biomass retrieval has been studied. Alum structural changes with pH were led to a full factorial design to address the effect of this chemical structure changes at different pH values. It is observed that the best flocculation efficiency could be achieved in the natural pH value of C. vulgaris growth medium (8.2) with less than 0.5 g/L flocculant addition, which would lead to the flocculation efficiency of more than 90%. An ensemble architecture of neural networks successfully employed for flocculation modeling.