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1.
Food Chem ; 368: 130770, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34399181

RESUMO

Amino acids and sulfonic acid derivatives (Taurine-Tau; Hypotaurine-HypTau; Homotaurine-HTau) of 26 different species of commercial macroalgae, microalgae and 10 algae-enriched food products from the market were quantified in a single chromatographic run. Tau and analogues were predominantly distributed in red species followed by green and brown species. Palmaria palmata, Gracilaria longissima and Porphyra sp. were the species with the highest content of Tau and total sulfonic acid derivatives (TAD). Notwithstanding, relatively high concentrations of HTau were found in green algae Ulva lactuca and G. vermicullophyla as well as in the brown algae Undaria pinnatifida. HTau and HypTau were found at lower concentrations than Tau in all species, except in Ulva lactuca. The samples with the highest protein content were the green species Chlorella vulgaris, Nannochloropsis, and Afanizomenon-flos aquae, followed by the red algae Gracilaria longissima and Gracilaria vermicullophyla. Samples of pasta formulated with algae ingredients contained the highest levels of sulfonic acid derivatives, evidencing that these products can provide levels of TAD comparable to those found in foods of animal origin. This study provides, for the first time, quantitative information regarding the distribution of sulfonic acid derivatives and total amino acids in multiple algae species as well as the nutritional impact of the inclusion of algae ingredients in commercial food matrices.


Assuntos
Chlorella vulgaris , Microalgas , Rodófitas , Alga Marinha , Aminoácidos , Animais , Alimentos Fortificados , Taurina/análogos & derivados
2.
Sci Total Environ ; 802: 149988, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525699

RESUMO

Microalgae such Chlorella vulgaris can effectively absorb nitrate and phosphate from contaminated water. This work characterized nitrate and phosphate removal from simulated agricultural runoff using C. vulgaris. Statistically designed experiments were used to model the following responses: (1) algal growth; (2) nitrate removal; (3) phosphate removal; (4) protein in the algal biomass; (5) chlorophyll content of the biomass; (6) the biomass phenolics content; and (7) the free radical scavenging antioxidant activity of the biomass. These response were modelled for the following key experimental factors: initial nitrate concentration in the simulated runoff (1080-3240 mg L-1, as NaNO3), initial phosphate concentration (20-60 mg L-1, as K2HPO4), photoperiod (8-24 h of light/day) and culture duration (5-15 days). The validated models were used to identify the factor levels to maximize the various responses. Nitrate removal was maximized at 85.6% when initial nitrate and phosphate concentrations were 2322 mg L-1 and 38 mg L-1 (N:P atom ratio ≈ 125:1), respectively, with a 17.2 h daily photoperiod in a 13-day culture. Phosphate removal was maximized at 95% when the initial nitrate and phosphate concentrations were 1402 mg L-1 and 56.7 mg L-1 (N:P ≈ 51:1), respectively, with a 15.7 h daily photoperiod in a 14.7-day culture. At least ~14 h of a daily photoperiod and a ~11-day culture period were required to maximize all the studied responses. C. vulgaris is edible and may be used as animal feed. Nutritional aspects of the biomass were characterized. Biomass with more than 24% protein could be produced. Under the best conditions, the chlorophyll (potential food colorants) content of the biomass was 8.5% and the maximum level of total phenolics (antioxidants) in the biomass was nearly 13 mg gallic acid equivalent g-1.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Nitratos , Fosfatos , Águas Residuárias , Água
3.
J Environ Manage ; 301: 113865, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34597951

RESUMO

Chlorella vulgaris (C. vulgaris) has attracted widespread attention because of its ability to absorb, enrich, and degrade typical endocrine-disrupting antibiotics (such as levofloxacin) in aquaculture wastewater. However, microplastic pollution in wastewater, which is becoming an increasingly severe problem, will exert a toxic effect on aquatic organisms (such as C. vulgaris and other microalgae). Polystyrene microplastics (PS-MPs), which are commonly found in freshwater aquaculture wastewater, are the most harmful. Therefore, clarifying the effects of PS-MPs on the ability of C. vulgaris to degrade typical endocrine-disrupting antibiotics in freshwater aquaculture wastewater and determining the mechanism of the effect are particularly important. The results of this study showed that under the stress of PS-MPs, the growth of C. vulgaris was significantly inhibited; the EPS-polysaccharide content per algal cell, EPS adsorption, intracellular enrichment and degradation of levofloxacin, total CYP450 content, and total CYP450 activity all decreased; and the relative expression of key genes related to the metabolic activity of algal cells, such as psbA, psaB, and rbcL, was generally downregulated. PS-MPs mainly affected the removal of a typical endocrine-disrupting antibiotic by C. vulgaris by altering adsorption, enrichment, and enzyme degradation. The results provide a reference for research on the impact of microplastic pollution on the treatment of freshwater aquaculture wastewater.


Assuntos
Chlorella vulgaris , Microalgas , Poluentes Químicos da Água , Aquicultura , Água Doce , Levofloxacino , Microplásticos , Plásticos , Poliestirenos , Águas Residuárias , Poluentes Químicos da Água/análise
4.
Sci Total Environ ; 804: 149878, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34508933

RESUMO

The removal of 18 bisphenols at wastewater relevant concentrations (µg L-1 range) was investigated and compared between Chlorella vulgaris cultures with pH adjusted to 6.8 and pH non-adjusted cultures where pH raised to above 10. Bisphenols with a high partition coefficient (log P > 6) partitioned to biomass soon after spiking, whereas bisphenols with a low partition coefficient (log P < 4) remained largely in the aqueous phase. Hydrophobic bisphenols and BPF isomers were removed to a large degree in pH adjusted conditions, while BPS and BPAF were the most recalcitrant. The overall average removal after 13 days was similar in both experiments, with 72 ± 2% and 73 ± 5% removed in pH non-adjusted and pH adjusted series, respectively. The removal correlated with chlorophyll a concentration for most bisphenols meaning that algae played a crucial role in their removal, while culture pH also governed the removal of some compounds.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Reatores Biológicos , Clorofila A , Águas Residuárias/análise
5.
Bioresour Technol ; 343: 126086, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34624468

RESUMO

The anaerobic co-digestion (AcoD) of microalgae is a prospective option for generating biomethane from renewable sources. This study investigates the effects of inoculum-to-substrate ratio (ISR), C/N ratio and biochar (BC) load on the AcoD of Chlorella vulgaris and cellulose. An initial augmentation of BC at ISR 0.5-0.9 and C/N ratio 10-30 offered a pH buffering effect and resulted in biomethane yields of 233-241 mL CH4/g VS, corresponding to 1.8-4.6 times the controls. BC addition ameliorated significantly AcoD, supporting the digestate stability at less favourable conditions. The effect of the process variables was further studied with a 23 factorial design and response optimisation. Under the design conditions, the variables had less influence over methane production. Higher ISRs and C/N ratios favoured AcoD, whereas increasing amounts of BC reduced biomethane yield but enhanced production rate. The factorial design highlighted the importance of BC-load on AcoD, establishing an optimum of 0.58 % (w/v).


Assuntos
Chlorella vulgaris , Anaerobiose , Biocombustíveis , Reatores Biológicos , Celulose , Carvão Vegetal , Digestão , Metano , Estudos Prospectivos
6.
Bioresour Technol ; 343: 126089, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34624471

RESUMO

The 4-aminobutyric acid (GABA) is important to produce bio-nylon 4 in biorefineries. First, a glutamate decarboxylase (GAD) was propagated in three different Escherichia coli strains to achieve 100% conversion from 1 M monosodium glutamate after optimization of the process. To make the process greener and more efficient, in situ CO2 adaptation and citrate feeding strategies to maintain the optimal pH value and 498 g/L of GABA was obtained. However, the process releases the equivalent amount of CO2. Therefore, CO2 generated from GABA production was completely sequestered in sodium hydroxide to form bicarbonate and applied in a coupling culture of Chlorella sorokiniana (CS) or Chlorella vulgaris (CV) to increase the biomass when combined with sodium bicarbonate and carbonic anhydrase. Further improvement of 1.65-fold biomass and 1.43-fold lipid content were occurred when supplying GABA to the culture. This integrative process provided the highest GABA production rate without CO2 release, forming an eco-friendly and carbon-neutral technology.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Carbono , Ácido gama-Aminobutírico
7.
Appl Microbiol Biotechnol ; 105(23): 8689-8701, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34724082

RESUMO

An efficient use of light is essential to achieve good performances in microalgae cultivation systems. This can be challenging particularly under solar conditions where light is highly dynamic (e.g., day/night cycles, rapid changes in wind and weather conditions). Microalgae display different mechanisms to optimize light use efficiency. In the short term, when high light is encountered, several processes of photoprotection can be involved to avoid cell damages (e.g., xanthophyll cycle). In the long term, when cells are exposed to a different light intensity, pigment content changes, i.e., photoacclimation. The purpose of this study is to investigate the photosynthetic response of Chlorella vulgaris cultures grown in closed lab-scale, torus-shape photobioreactor under well-controlled light conditions, namely, constant and dynamic light transitions. Experiments were conducted in continuous mode with detailed characterization of the light attenuation conditions for each condition, as represented by the mean rate of photon absorption (MRPA), so as to characterize the time responses of the photosynthetic cells toward light changes. This enables to observe short-term and long-term responses with their own characteristic times. The mechanisms involved were found to be different between increasing and decreasing light transitions. Furthermore the MRPA was found a valuable parameter to relate the effect of light to biological responses (i.e., pigment changes) under constant light and dynamic light conditions.Key points• MRPA proved valuable to relate C. vulgaris responses to light changes.• A linear evolution was found between pigment content and MRPA in continuous light.• A rising PFD step induced fast protection and acclimation mechanisms.


Assuntos
Chlorella vulgaris , Microalgas , Fotobiorreatores , Fotossíntese
8.
Waste Manag ; 136: 266-272, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34717214

RESUMO

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 ± 0.09 g l-1) compared to DIG-OFMSW (1.05 ± 0.13 g l-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.


Assuntos
Chlorella vulgaris , Microalgas , Biocombustíveis , Biomassa , Esgotos
9.
Chemosphere ; 282: 131044, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470146

RESUMO

The wide application of α-Fe2O3 nanoparticles (NPs) in different fields has resulted in release and accumulation of these materials into the aquatic ecosystem. Therefore, it is important to understand the potential impact of these NPs on aquatic organisms especially primary producers i.e., microalgae. Present study aimed to investigate the bioavailability and the effect of α-Fe2O3 NPs on growth of iron deprived cells of Chlorella vulgaris. Results showed that α-Fe2O3 NPs are not available as iron source to support the growth of C. vulgaris. Moreover,α-Fe2O3 NPs induced stress condition to C. vulgaris, which were reflected in its growth rates, total lipid contents, fatty acid profile and cell morphology. Specifically, low concentrations of α-Fe2O3 NPs (0.1, 0.5, 2.5, 5, 10 mg/L) showed similar growth profile and total lipid contents at both exponential and stationary growth phases. At 50 and 100 mg/L α-Fe2O3 NPs concentrations biomass reduced by 41.2% and 83.7% whereas total lipid contents increased by 39.7% and 25.5% respectively at exponential growth phase along with reduction in fatty acids. The results illustrated novel insights into the microalgal interaction with nanoparticles, providing fundamental knowledge for the development of future microalgae ecology and cultivation technology.


Assuntos
Chlorella vulgaris , Microalgas , Nanopartículas , Disponibilidade Biológica , Biomassa , Ecossistema , Ácidos Graxos
10.
Bioresour Technol ; 341: 125857, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34523553

RESUMO

Pyrolysis characteristics and bio-oil of Chlorella vulgaris were investigated under SiC and ZnO (SZ) mixture (compound additive) with various mixing ratios (S/Z = 10:0, 7:3, 5:5, 3:7, 0:10) and addition amounts (5%, 10%, 15%) by thermogravimetric analysis and GC-MS. At three experimental groups of 10% compound additive, as ZnO in compound additive increased, maximum weight loss rate (Rp) increased, the time (tp) corresponding to Rp and the weight stabilization time (tf) first decreased and then increased, while average rate of weight loss (Ra) and total weight loss (M) first increased and then decreased; maximum temperature rising rate (Hx) and average rate of temperature rising (Hg) increased, while the time (tx) corresponding to Hx decreased. Compound additives reduced the bio-oil yield, increased the gas yield, and reduced the acid compounds in bio-oil. Besides, it might promote the production of alicyclic hydrocarbons and oxygen/nitrogen-containing long-chain compounds.


Assuntos
Chlorella vulgaris , Biocombustíveis , Temperatura Alta , Micro-Ondas , Pirólise , Temperatura
11.
Bioresour Technol ; 341: 125892, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34523555

RESUMO

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.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Meios de Cultura , Resíduos Industriais , Lipídeos , Águas Residuárias
12.
Artigo em Inglês | MEDLINE | ID: mdl-34360075

RESUMO

Nanoparticles have applications in various fields such as manufacturing and materials synthesis, the environment, electronics, energy harvesting, and medicine. Besides many applications of nanoparticles, further research is required for toxic environmental effect investigation. The toxic effect of titanium dioxide nanoparticles on the physiology of the green alga Chlorella vulgaris was studied with a widely used pesticide, imidacloprid (IMD). Chlorella vulgaris was exposed for 120 h in Bold's basal medium to different toxic compounds, such as (i) a high concentration of TiO2 nanoparticles, 150-2000 mg/L, usually optimised in the photocatalytic degradation of wastewater, (ii) an extremely toxic pesticide for the aquatic environment, imidacloprid, in concentrations ranging from 5 to 40 mg/L, (iii) TiO2 nanoparticles combined with imidacloprid, usually used in a photocatalytic system. The results show that the TiO2 nanoparticles and IMD inhibited Chlorella vulgaris cell growth and decreased the biovolume by approximately 80% when 2 g/L TiO2 was used, meaning that the cells devised a mechanism to cope with a potentially stressful situation; 120 h of Chlorella vulgaris exposure to 40 mg/L of IMD resulted in a 16% decreased cell diameter and a 41% decrease in cell volume relative to the control sample, associated with the toxic effect of pesticides on the cells. Our study confirms the toxicity of nanoparticles through algal growth inhibition with an effective concentration (EC50) value measured after 72 h of 388.14 mg/L for TiO2 and 13 mg/L for IMD in a single-toxic system. The EC50 of TiO2 slowly decreased from 258.42 to 311.11 mg/L when IMD from 5 to 20 mg/L was added to the binary-toxic system. The concentration of TiO2 in the binary-toxic system did not change the EC50 for IMD, and its value was 0.019 g/L. The photodegradation process of imidacloprid (range of 5-40 mg/L) was also investigated in the algal medium incubated with 150-600 mg/L of titanium dioxide.


Assuntos
Chlorella vulgaris , Poluentes Químicos da Água , Neonicotinoides/toxicidade , Nitrocompostos , Titânio/toxicidade
13.
Sci Total Environ ; 790: 148174, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34380256

RESUMO

To confront with energy crisis, microalgae as the promising feedstock have a great potential in exploring renewable energy field, whereas the high costs related to medium preparation and biomass harvesting are the main bottleneck to hinder the development on a large scale. Though cultivation of filamentous fungi for microalgae harvesting is an efficient, sustainable and emerging method, and the studies on specific mechanisms and spent medium recycling for efficiency improvement as well as resource saving through a co-pelletization mode are urgently needed. Hence, in this study, the harvesting process of autotrophic microalgae Chlorella vulgaris by pre-cultured Aspergillus oryzae pellets was investigated systematically. The highest efficiency (99.23%) was obtained within 5 h under the optimized conditions of 30 °C, 130 rpm and fungi:algae ratio of 1:1 on a dry weight basis without demand for pH adjustment (initial value on 9.68). Charge neutralization was not the main mechanisms involved in fungi-algae aggregations, and the functional group changes on cell surfaces as well as secreted metabolites in medium could be mainly responsible for inducing the bioflocculation process. After harvesting, separated water could also effectively support microalgae re-growth. The biomass concentration in medium with 50% recycling was higher than that in fresh medium, while lipid content was increased from 24.37% to 33.97% in fully recycled medium. These results indicated that the pellet-assisted mode for algal harvesting is a promising way to promote biofuel production and resource recycling.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Floculação , Fungos
14.
Bioresour Technol ; 340: 125669, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34339996

RESUMO

This study aims to elucidate the mechanisms governing the harvesting efficiency of Chlorella vulgaris by flocculation using a cationic polymer. Flocculation efficiency increased as microalgae culture matured (i.e. 35-45, 75, and > 97% efficiency at early, late exponential, and stationary phase, respectively. Unlike the negative impact of phosphate on flocculation in traditional wastewater treatment; here, phosphorous residue did not influence the flocculation efficiency of C. vulgaris. The observed dependency of flocculation efficiency on growth phase was driven by changes in microalgal cell properties. Microalgal extracellular polymeric substances (EPS) in both bound and free forms at stationary phase were two and three times higher than those at late and early exponential phase, respectively. Microalgae cells also became more negatively charged as they matured. Negatively charged and high EPS content together with the addition of high molecular weight and positively charged polymer could facilitate effective flocculation via charge neutralisation and bridging.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Floculação , Polímeros
15.
Water Res ; 203: 117464, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34371233

RESUMO

This work intends to promote the growth of microalgae biomass with simultaneous remediation of an agro-industrial wastewater. Winery wastewater (WW) was used as growth media for the cyanobacteria Arthrospira maxima and the green microalgae Scenedesmus obliquus, Auxenochlorella protothecoides and Chlorella vulgaris, under mixotrophic and heterotrophic conditions. The latter species stands out under mixotrophic conditions, with removals of TOC and TN above 90%. Biomass production and pollutant removal were influenced by the initial WW concentration. Maximum removal values within 8 days of incubation were 92, 91, 49 and 40% for COD, TN, polyphenols and P-PO4, respectively, and 147.5 mg L-1 d-1 of biomass productivity. C. vulgaris biomass showed higher carotenoid content (maximum of 8.7 mg/g) when grown in WW, compared to autotrophic conditions (6.5 mg/g), making the bioremediation process more viable with the production of valuable by-products such as pigments. As the pollutant load removed by the microalgae does not allow reach the legal limits of release treated waters in natural water courses, a tertiary treatment process was applied. A post-treatment by photocatalysis in a UV LEDs photoreactor with TiO2-supported in Raschig rings was proposed for the removal of COD and polyphenols from a high loaded WW. The heterogeneous photocatalytic process was efficient in removing 80% of total polyphenols and 40% of COD, allowing the release of the treated water in superficial water courses since complies with the legal limits (COD below 150 mg L-1).


Assuntos
Chlorella vulgaris , Microalgas , Purificação da Água , Biomassa , Nitrogênio , Titânio , Águas Residuárias
16.
Bioresour Technol ; 340: 125703, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34371337

RESUMO

This work was the first time to evaluate the ability of an isolated Chlorella vulgaris MBFJNU-1 to remove nutrients of original swine wastewater (OSW) and fix carbon dioxide (CO2) under outdoor conditions in a simultaneous manner using column photobioreactors. The results showed that microalga cultivated at 3% CO2 in a batch mode achieved the highest biomass and CO2 fixation rate. Then, a semi-continuous process for OSW treatment and CO2 fixation simultaneously by microalga was established and the renewal rate of this process was deeply investigated. Microalga cultivated at 3% CO2 and 80% renewal rate gave the highest productivities of total biomass, CO2 fixation and the greatest average removal rates of total nitrogen, N-NH4+, total phosphorus and chemical oxygen demand. Taken together, C. vulgaris MBFJNU-1 was the promising microalga under outdoor conditions for swine wastewater treatment and CO2 fixation simultaneously for biofuels and biofertilizer production.


Assuntos
Chlorella vulgaris , Microalgas , Animais , Biomassa , Dióxido de Carbono , Nitrogênio , Fotobiorreatores , Suínos , Águas Residuárias
17.
Arch Microbiol ; 203(9): 5525-5532, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34426852

RESUMO

'Cultured food' has tremendous potential as a sustainable meat alternative. Increased cultured food production is increasing the amount of waste medium from cell culture. Nitrogen- and phosphorus-containing compounds in waste medium can cause eutrophication of water bodies. Currently, microalgae are used in energy production, environmental protection, agriculture and pharmaceutical and health food industries. Here, we used the microalgae, Chlorococcum littorale and Chlorella vulgaris and the waste medium of C2C12 cells for a case study. We found that 80% and 26% of ammonia and 16% and 15% of phosphorus in the waste medium were consumed by C. littorale and C. vulgaris, respectively. In addition, C. littorale and C. vulgaris proliferated 3.2 folds and 1.6 folds, respectively, after seven days in the waste medium that was enhanced by adjusting medium salt concentration. This report demonstrates the potential of sustainability for solving the issue of waste medium production during the production of cultured food.


Assuntos
Chlorella vulgaris , Alimentos e Bebidas Fermentados , Microalgas , Animais , Biomassa , Nitrogênio , Águas Residuárias
18.
Sci Rep ; 11(1): 16741, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34408229

RESUMO

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).


Assuntos
Alginatos , Chlorella vulgaris/crescimento & desenvolvimento , Sistemas de Liberação de Medicamentos , Riboflavina/química , Sargassum/química , Alginatos/química , Alginatos/isolamento & purificação , Alginatos/farmacologia
19.
Sci Total Environ ; 800: 149504, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34426316

RESUMO

The inherent metabolic versatility of Chlorella vulgaris that enables it to metabolize both inorganic and organic carbon under various trophic modes of cultivation makes it a promising candidate for industrial applications. To shed light on the metabolic flexibility of this microalga, time resolved proteomic and metabolomic studies were conducted in three distinct trophic modes (autotrophic, heterotrophic, mixotrophic) at two growth stages (end of linear growth at 6 days and during nutrient deprivation at 10 days). Sweet sorghum bagasse (SSB) hydrolysate was supplied to the cultivation medium as a renewable source of organic carbon mainly in the form of glucose. Integrated multi-omics data showed improved nitrogen assimilation, re-allocation, and recycling and increased levels of photosystem II (PS II) proteins indicating effective cellular quenching of excess electrons during mixotrophy. As external addition of organic carbon (glucose) to the cultivation medium decreases the cell's dependence on photosynthesis, an upregulation in the mitochondrial electron transport chain was recorded that led to increased cellular energy generation and hence higher growth rates under mixotrophy. Moreover, upregulation of the lipid-packaging proteins caleosin and 14_3_3 domain-containing protein resulted in maximum expression during mixotrophy suggesting a strong correlation between lipid synthesis, stabilization, and assembly. Overall, cells cultivated under mixotrophy showed better nutrient stress tolerance and redox balancing leading to higher biomass and lipid production. The study offers a panoramic view of the microalga's metabolic flexibility and contributes to a deeper understanding of the altered biochemical pathways that can be exploited to enhance algal productivity and commercial potential.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Processos Heterotróficos , Proteômica , Açúcares
20.
J Food Biochem ; 45(10): e13914, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34459004

RESUMO

This study was aimed to investigate the effect of microalgae Chlorella vulgaris (C. vulgaris) on nonalcoholic fatty liver disease (NAFLD)-related complications induced by high-fat diet (HFD). Fifty adult male rats were divided into six groups. Control group and HFD group treated with or without C. vulgaris 5% and 10%. Biochemical parameters in serum were measured by spectrophotometric and enzyme-linked immunosorbent assay (ELISA) methods. The relative gene expression levels of Tumor Necrosis Factor-alpha (TNF-α), NF-kappa B (NF-ƙB), and p38 Mitogen-Activated Protein Kinases (p38 MAPK) in the liver were assessed by using quantitative real-time PCR, while the protein levels of NF-ƙB and TNF-α in the liver homogenate were determined by ELISA. The effects of HFD significantly were reversed by C. vulgaris, especially at a 10% dose. Therefore, it can be concluded that C. vulgaris therapeutically could be useful to improve NAFLD and its complications. PRACTICAL APPLICATIONS: It is established that NAFLD is associated with the resistance to insulin, dyslipidemia, and inflammation. Accordingly, modulating of these conditions may be useful in the management of NAFLD. Our results showed the effectiveness of C. vulgaris against NAFLD-related complication through the alleviating insulin resistance, dyslipidemia and also down-regulation of inflammatory genes in p38 MAPK/TNF-α/NF-ƙB pathway. The results of our study may be useful for scientist to prepare an effective supplement from C. vulgaris to overcoming NAFLD-related complications.


Assuntos
Chlorella vulgaris , Dislipidemias , Resistência à Insulina , Hepatopatia Gordurosa não Alcoólica , Animais , Dislipidemias/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Ratos
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