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1.
Sci Total Environ ; 692: 259-266, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31349167

RESUMO

Traditional swine manure treatments are not fully effective in the removal of veterinary drugs. Moreover, they are costly and entail a significant carbon footprint in many cases. Innovative biological approaches based on phototrophic microorganisms have recently emerged as promising alternatives to overcome those limitations. This work evaluated the removal of 19 veterinary drugs (i.e., 16 antibiotics, 1 analgesic, 1 anti-parasitic and 1 hormone) from piggery wastewater (PWW) in two open photobioreactors (PBR) operated with a consortium of microalgae-bacteria (AB-PBR) and purple photosynthetic bacteria (PPB-PBR). Multiple hydraulic retention times (HRT), in particular 11, 8 and 4 days, were tested during stage I, II and III, respectively. Ten out of 19 target compounds were detected with inlet drug concentrations ranging from 'non-detected' (n.d.) to almost 23,000 ng L-1 for the antibiotic oxytetracycline. Moreover, three of the antibiotics (i.e., enrofloxacin, sulfadiazine and oxytetracycline) were found at concentrations above the analytical linearity range in some or all of the samples under study. AB-PBR supported higher removal efficiencies (REs) than PPB-PBR, except for danofloxacin. Overall, REs progressively decreased when decreasing the HRT. The highest REs (>90%) were observed for doxycycline (95 ±â€¯3%) and oxytetracycline (93 ±â€¯3%) in AB-PBR during stage I. The other drugs, except sulfadimidine that was the most recalcitrant, showed REs above 70% during stage I in the same photobioreactor. In contrast, no removal was observed for danofloxacin in AB-PBR during stage III, sulfadimidine in PPB-PBR during stage III or marbofloxacin in PPB-PBR during the entire experiment.


Assuntos
Bactérias/metabolismo , Microalgas/metabolismo , Consórcios Microbianos , Fotobiorreatores/microbiologia , Drogas Veterinárias/análise , Eliminação de Resíduos Líquidos/métodos , Criação de Animais Domésticos , Animais , Proteobactérias/metabolismo , Sus scrofa , Eliminação de Resíduos Líquidos/instrumentação , Águas Residuárias/análise
2.
J Biotechnol ; 303: 37-45, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31351109

RESUMO

Consecutive dark-fermentation and photo-fermentation stages were investigated for a profitable circular bio-economy. H2 photo-production versus poly(3-hydroxybutyrate) (P3HB) accumulation is a modern biotechnological approach to use agro-food industrial byproducts as no-cost rich-nutrient medium in eco-sustainable biological processes. Whey and molasses are very important byproducts rich in nutrients that lactic acid bacteria can convert, by dark-fermentation, in dark fermented effluents of whey (DFEW) and molasses (DFEM). These effluents are proper media for culturing purple non-sulfur bacteria, which are profitable producers of P3HB and H2. The results of the present study show that Lactobacillus sp. and Rhodopseudomonas sp. S16-VOGS3 are two representative genera for mitigation of environmental impact. The highest productivity of P3HB (4.445 mg/(L·h)) was achieved culturing Rhodopseudomonas sp. S16-VOGS3, when feeding the bacterium with 20% of DFEM; the highest H2 production rate of 4.46 mL/(L·h) was achieved when feeding the bacterium with 30% of DFEM.


Assuntos
Lactobacillus/crescimento & desenvolvimento , Melaço/microbiologia , Rodopseudomonas/crescimento & desenvolvimento , Soro do Leite/microbiologia , Técnicas de Cultura Celular por Lotes , Fermentação , Hidrogênio/metabolismo , Hidroxibutiratos/análise , Lactobacillus/metabolismo , Fotobiorreatores/microbiologia , Poliésteres/análise , Rodopseudomonas/metabolismo
3.
Chemosphere ; 234: 356-364, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31228837

RESUMO

The potential of a novel anaerobic/aerobic algal-bacterial photobioreactor for the treatment of synthetic textile wastewater (STWW) was here assessed. Algal-bacterial symbiosis supported total organic carbon, nitrogen and phosphorous removal efficiencies of 78 ±â€¯2%, 47 ±â€¯2% and 26 ±â€¯2%, respectively, at a hydraulic retention time (HRT) of 8 days. A decrease in the HRT from 8 to 4 and 2 days resulted in a slight decrease in organic carbon and phosphate removal, but a sharp decrease in nitrogen removal. Moreover, an efficient decolorization of 99 ±â€¯1% and 96 ±â€¯3% for disperse orange-3 and of disperse blue-1, respectively, was recorded. The effective STWW treatment supported by the anaerobic/aerobic algal-bacterial photobioreactor was confirmed by the reduction in wastewater toxicity towards Raphanus sativus seed germination and growth. These results highlighted the potential of this innovative algal-bacterial photobioreactor configuration for the treatment of textile wastewater and water reuse.


Assuntos
Fotobiorreatores/microbiologia , Têxteis , Águas Residuárias/toxicidade , Purificação da Água/métodos , Bactérias/metabolismo , Carbono/isolamento & purificação , Clorófitas/metabolismo , Cor , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/análise , Purificação da Água/instrumentação
4.
Int J Biol Macromol ; 135: 821-828, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31158419

RESUMO

The main goal of this investigation was setting up a growth strategy to separate H2 evolution from P3HB synthesis in order to increase cumulative P3HB in Rhodopseudomonas cells. The accumulation of poly-3-hydroxybutyrate (P3HB) was investigated culturing Rhodopseudomonas sp. S16-VOGS3 with three carbon substrates either as acetate, butyrate or lactate and with two nitrogen sources either as ammonium or glutamate. The investigation was carried out under several stress conditions caused by single or double nutrient deficiency. The content of P3HB in cell dry weight (CDW) was 21.8% with lactate; 24.6% with acetate and 27.6% with butyrate under sulfur deficient conditions. The P3HB content increased significantly culturing Rhodopseudomonas sp. S16-VOGS3 with butyrate following three phases of growth: phase-1, nutrient sufficient conditions; phase-2, nitrogen-deficiency and phase-3, sulfur-deficient conditions. Under this last phase, the highest P3HB content was achieved (34.4% of CDW). A combined production of P3HB and molecular H2 was obtained when Rhodopseudomonas sp. S16-VOGS3 was cultured with either acetate or butyrate under nitrogen sufficiency (glutamate) or nitrogen deficiency.


Assuntos
Biotecnologia/métodos , Meios de Cultura/química , Hidrogênio/metabolismo , Hidroxibutiratos/metabolismo , Fotobiorreatores/microbiologia , Poliésteres/metabolismo , Rodopseudomonas/crescimento & desenvolvimento , Rodopseudomonas/metabolismo , Biotecnologia/instrumentação , Ácidos Carboxílicos/metabolismo , Enxofre/metabolismo
5.
J Biotechnol ; 297: 41-48, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30898687

RESUMO

Scaling of phototrophic bioprocesses can be extremely challenging especially when reactor types in the considered scales differ. In this study, the mean integral photon flux density was used to transfer light-dependent growth kinetics of Nannochloropsis salina 40.85 and Nannochloropsis gaditana 2.99 grown with constant LED irradiation from flat-plate gas-lift photobioreactors (0.09 m2) to thin-layer cascade photobioreactors (8 m2). Even though completely different reactors were used, comparable growth rates were achieved on both scales with both strains by application of comparable mean light availabilities in the microalgae suspensions. In contrast, the light-dependent growth kinetics change significantly when irradiation varies dynamically (day-night cycles). The maximum intra-day growth rate of N. salina with dynamic climate simulation was doubled to 0.07 h-1 compared to constant irradiation, but tolerance of the microalgae against excessive irradiation was drastically reduced compared to constant irradiation. Because of that, predicting growth of N. salina in a physically simulated day-night climate would require the determination of the light-dependence of growth with dynamically varying conditions.


Assuntos
Luz , Microalgas/crescimento & desenvolvimento , Microalgas/efeitos da radiação , Fotobiorreatores/microbiologia , Processos Fototróficos/efeitos da radiação , Técnicas de Cultura Celular por Lotes , Biomassa , Cinética , Região do Mediterrâneo , Estações do Ano
6.
J Biotechnol ; 295: 28-36, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30853636

RESUMO

This study disserts on the exploitation of olive mill wastewater (OMW) for the production of both bio-based poly-ß-hydroxybutyrate (PHB) and hydrogen (H2) by using the residual effluent as feedstock for growing purple bacteria after the recovery of hydroxytyrosol-rich mixtures. In particular, Rhodopseudomonas sp. S16-FVPT5 was fed with either the virgin OMW or dephenolized-OMW (d-OMW). For polyphenols removal, the OMW was treated with activated carbon; subsequently, acidified ethanol (pH = 3.1) at 50 °C was used as extractor solvent for obtaining hydroxytyrosol-rich mixtures. The maximum hydroxytyrosol content in the resultant polyphenolic mixture was 2.02 g/L. The highest co-production of PHB (315 mg PHB/L) and H2 (2236 mL H2/L) were achieved feeding Rhodopseudomonas sp. S16-FVPT5 with pure d-OMW. The highest hydrogen yield (4.55 L(H2)/Ld-OMW) was obtained feeding the bacterium with d-OMW, diluted at 25%; by increasing the content of d-OMW into the culture broth the hydrogen yield progressively decreased. Lower results were obtained by feeding the bacterium with a synthetic medium, the cumulative hydrogen was 1855 mL H2/L); the PHB was 101 mg PHB/L. The highest theoretical light conversion efficiency was 2.36% with the synthetic medium and 1.99% when feeding Rhodopseudomonas sp. S16-FVPT5 with d-OMW diluted with water 50%, v/v.


Assuntos
Olea/química , Álcool Feniletílico/análogos & derivados , Fotobiorreatores/microbiologia , Rodopseudomonas/metabolismo , Águas Residuárias/química , Hidrogênio/análise , Hidrogênio/metabolismo , Resíduos Industriais , Álcool Feniletílico/química , Álcool Feniletílico/metabolismo , Polifenóis/análise , Polifenóis/metabolismo , Eliminação de Resíduos Líquidos
7.
Bioresour Technol ; 281: 10-17, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30784997

RESUMO

The potential of purple phototrophic bacteria (PPB) for the simultaneous treatment of piggery wastewater (PWW) and biogas upgrading was evaluated batchwise in gas-tight photobioreactors. PWW dilution was identified as a key parameter determining the efficiency of wastewater treatment and biomethane quality in PPB photobioreactors. Four times diluted PWW supported the most efficient total organic carbon (TOC) and total nitrogen removals (78% and 13%, respectively), with CH4 concentrations of 90.8%. The influence of phosphorous concentration (supplementation of 50 mg L-1 of P-PO43-) on PPB-based PWW treatment coupled to biogas upgrading was investigated. TOC removals of ≈60% and CH4 concentrations of ≈90.0% were obtained regardless of phosphorus supplementation. Finally, the use of PPB and algal-bacterial consortia supported CH4 concentrations in the upgraded biogas of 93.3% and 73.6%, respectively, which confirmed the potential PPB for biogas upgrading coupled to PWW treatment.


Assuntos
Biocombustíveis , Águas Residuárias/química , Biomassa , Microalgas/metabolismo , Nitrogênio/isolamento & purificação , Fotobiorreatores/microbiologia
8.
Appl Microbiol Biotechnol ; 103(8): 3571-3580, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30809712

RESUMO

Graesiella emersonii was cultivated in an osmotic membrane photobioreactor (OMPBR) for nutrients removal from synthetic wastewater in continuous mode. At 1.5 days of hydraulic retention time and under continuous illumination, the microalgae removed nitrogen (N) completely at influent NH4+-N concentrations of 4-16 mg/L, with removal rates of 3.03-12.1 mg/L-day. Phosphorus (P) removal in the OMPBR was through biological assimilation as well as membrane rejection, but PO43--P assimilation by microalgae could be improved at higher NH4+-N concentrations. Microalgae biomass composition was affected by N/P ratio in wastewater, and a higher N/P ratio resulted in higher P accumulation in the biomass. The OMPBR accumulated about 0.35 g/L biomass after 12 days of operation under continuous illumination. However, OMPBR operation under 12 h light/12 h dark cycle lowered biomass productivity by 60%, which resulted in 20% decrease in NH4+-N removal and nearly threefold increase in PO43--P accumulation in the OMPBR. Prolonged dark phase also affected carbohydrate accumulation in biomass, although its effects on lipid and protein accumulation were negligible. The microalgae also exhibited high tendency to aggregate and settle, which could be attributed to reduction in cell surface charge and enrichment of soluble algal products in the OMPBR. Due to a relatively shorter operating period, membrane biofouling and salt accumulation did not influence the permeate flux significantly. These results improve the understanding of the effects of N/P ratio and light/dark cycle on biomass accumulation and nutrients removal in the OMPBR.


Assuntos
Microalgas/crescimento & desenvolvimento , Nutrientes/isolamento & purificação , Fotobiorreatores/microbiologia , Fotoperíodo , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/instrumentação , Incrustação Biológica , Biomassa , Metabolismo dos Carboidratos , Clorófitas/crescimento & desenvolvimento , Clorófitas/metabolismo , Membranas Artificiais , Microalgas/metabolismo , Nitrogênio/química , Nitrogênio/isolamento & purificação , Nitrogênio/metabolismo , Nutrientes/química , Nutrientes/metabolismo , Osmose , Fósforo/química , Fósforo/isolamento & purificação , Fósforo/metabolismo , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
9.
Prep Biochem Biotechnol ; 49(3): 255-269, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30794071

RESUMO

The main focus of the work is to study Chlorella pyrenoidosa mediated photoautotrophic production of lipid in a bubble column photobioreactor using CO2 as carbon source under natural diurnal outdoor sunlight. The limiting and inhibiting concentrations of CO2 in sparging gas, nitrogen inhibition, reversibility of the CO2 inhibition on growth, and lipid production have been investigated under natural sunlight. A process model coupled with light distribution inside the culture has been developed considering different concentration of dissolved CO2 and urea, repression of nitrogen on lipid production under natural sunlight diurnal in nature in a bubble column reactor. The biomass titer of 4.6 g/L with 10% CO2 has been achieved within 5 days of culture under sunlight. A two stage photoautotrophic lipid production strategy in a sintered disc bubble column photobioreactor under natural sunlight has been developed. 30% (w/w-DCW) lipid within 5 days of lipid induction period has been achieved. The biomass productivity of 0.91 ± 0.01 gm/L/day in growth period with sufficient urea and lipid productivity of 410 ± 12 mg/L/day in last 2 days of urea starvation period have been achieved in outdoor photoautotrophic cultivation under natural sunlight using CO2 as carbon source.


Assuntos
Biocombustíveis/microbiologia , Chlorella/metabolismo , Ácidos Graxos/biossíntese , Fotobiorreatores/microbiologia , Dióxido de Carbono/metabolismo , Modelos Biológicos , Fosfatos/metabolismo , Luz Solar , Ureia/metabolismo
10.
Bioresour Technol ; 279: 43-49, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30710819

RESUMO

The performance of photosynthetic biogas upgrading coupled to wastewater treatment was evaluated in an outdoors high rate algal pond (HRAP) interconnected to an absorption column at semi-industrial scale. The influence of biogas flowrate (274, 370 and 459 L h-1), liquid to biogas ratio (L/G = 1.2, 2.1 and 3.5), type of wastewater (domestic versus centrate) and hydraulic retention time in the HRAP (HRT) on the quality of the biomethane produced was assessed. The highest CO2 and H2S removal efficiencies (REs) were recorded at the largest L/G due to the higher biogas-liquid mass transfer at increasing liquid flowrates. No significant influence of the biogas flowrate on process performance was observed, while the type of wastewater was identified as a key operational parameter. CO2 and H2S-REs of 99% and 100% at a L/Gmax = 3.5 were recorded using centrate. The maximum CH4 content in the biomethane (90%) was limited by N2 and O2 desorption.


Assuntos
Biocombustíveis , Fotobiorreatores , Fotossíntese , Tanques , Bactérias , Fotobiorreatores/microbiologia
11.
Bioresour Technol ; 280: 112-117, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30763863

RESUMO

The influence of the liquid-to-biogas ratio (L/G) and alkalinity on methane quality was evaluated in a 11.7 m3 outdoors horizontal semi-closed tubular photobioreactor interconnected to a 45-L absorption column (AC). CO2 concentrations in the upgraded methane ranged from <0.1 to 9.6% at L/G of 2.0 and 0.5, respectively, with maximum CH4 concentrations of 89.7% at a L/G of 1.0. Moreover, an enhanced CO2 removal (mediating a decrease in CO2 concentration from 9.6 to 1.2%) and therefore higher CH4 contents (increasing from 88.0 to 93.2%) were observed when increasing the alkalinity of the AC cultivation broth from 42 ±â€¯1 mg L-1 to 996 ±â€¯42 mg L-1. H2S was completely removed regardless of the L/G or the alkalinity in AC. The continuous operation of the photobioreactor with optimized operating parameters resulted in contents of CO2 (<0.1%-1.4%), H2S (<0.7 mg m-3) and CH4 (94.1%-98.8%) complying with international regulations for methane injection into natural gas grids.


Assuntos
Biocombustíveis , Fotobiorreatores/microbiologia , Álcalis , Biomassa , Dióxido de Carbono/metabolismo , Concentração de Íons de Hidrogênio , Metano/biossíntese
12.
Artigo em Inglês | MEDLINE | ID: mdl-30663543

RESUMO

The aim of this study was to evaluate the mitigation of greenhouse gasses generated in the anaerobic digestion process of physicochemical sludges by evaluating the effect of CO2 supply and light intensity requirements on the growth of microalga Chlorella spp. and measuring the consumption of CO2. The best conditions at a laboratory scale were performed in an airlift photobioreactor (PBR) at pilot-scale plant (26 L) during 60 days with a CO2 supply of 2% v v-1 from an electric generator coupled to an anaerobic digestion of physicochemical sludge process. The maximum %CO2 consumed was 91.92% which was reached in the seventh supply cycle and biomass production was 2.18 g L-1. The results obtained showed that airlift-type PBRs are a suitable complement for anaerobic digestion of physicochemical sludge technologies in order to reduce emissions of greenhouse gases produced during the combustion of biogas.


Assuntos
Biocombustíveis/análise , Dióxido de Carbono/análise , Chlorella/crescimento & desenvolvimento , Gases de Efeito Estufa/análise , Fotobiorreatores/microbiologia , Esgotos/química , Anaerobiose , Biomassa
13.
J Vis Exp ; (143)2019 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-30663711

RESUMO

There is significant interest in the study of microalgae for engineering applications such as the production of biofuels, high value products, and for the treatment of wastes. As most new research efforts begin at laboratory scale, there is a need for cost-effective methods for culturing microalgae in a reproducible manner. Here, we communicate an effective approach to culture microalgae in laboratory-scale photobioreactors, and to measure the growth and neutral lipid content of that algae. Instructions are also included on how to set up the photobioreactor system. Although the example organisms are species of Chlorella and Auxenochlorella, this system can be adapted to cultivate a wide range of microalgae, including co-cultures of algae with non-algae species. Stock cultures are first grown in bottles to produce inoculum for the photobioreactor system. Algae inoculum is concentrated and transferred to photobioreactors for cultivation in batch mode. Samples are collected daily for the optical density readings. At the end of the batch culture, cells are harvested by centrifuge, washed, and freeze dried to obtain a final dry weight concentration. The final dry weight concentration is used to create a correlation between the optical density and the dry weight concentration. A modified Folch method is subsequently used to extract total lipids from the freeze-dried biomass and the extract is assayed for its neutral lipid content using a microplate assay. This assay has been published previously but protocol steps were included here to highlight critical steps in the procedure where errors frequently occur. The bioreactor system described here fills a niche between simple flask cultivation and fully-controlled commercial bioreactors. Even with only 3-4 biological replicates per treatment, our approach to culturing algae leads to tight standard deviations in the growth and lipid assays.


Assuntos
Bioensaio/instrumentação , Técnicas de Cultura de Células/instrumentação , Lipídeos/análise , Microalgas/crescimento & desenvolvimento , Fotobiorreatores/microbiologia , Biomassa , Chlorella/crescimento & desenvolvimento
14.
Sci Total Environ ; 662: 32-40, 2019 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-30684900

RESUMO

This work evaluates the removal of five pharmaceuticals and personal care products, i.e., ibuprofen, naproxen, salicylic acid, triclosan and propylparaben, from urban wastewater under two novel algal-bacterial photobioreactor settings. The first configuration (phase A) consisted of an anoxic-aerobic photobioreactor operating at a hydraulic retention time (HRT) of 2d at different concentrations of total organic carbon (TOC) (90mgL-1-200mgL-1). In the second configuration (phase B) an anaerobic step was introduced before the anoxic tank to set a photosynthetic A2O process. In this phase, the HRT varied between 3 and 4d and the TOC was kept constant at 200mgL-1. In addition, the impact of external aeration in the aerobic photobioreactor was assessed. The maximum removals for ibuprofen, naproxen, salicylic acid, triclosan and propylparaben (94±1%, 52±43%, 98±2%, 100±0%, 100±0%, respectively) were recorded during phase B. In phase A, low TOC concentrations triggered higher ibuprofen and naproxen removals likely due to the high contribution of biological oxidation on their removal. In phase B, total or very high removal efficiencies were observed for ibuprofen, propylparaben and triclosan independently on the operating conditions. In contrast, the removal efficiency of naproxen and salicylic acid decreased when the HRT dropped from 4 to 3d in the absence of external aeration, which suggests that biodegradation played a key role in their removal. In addition, sorption might have contributed to the elimination of triclosan and propylparaben from the wastewater.


Assuntos
Bactérias/metabolismo , Microalgas/metabolismo , Fotobiorreatores/microbiologia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Aerobiose , Anaerobiose , Anti-Infecciosos/análise , Anti-Inflamatórios não Esteroides/análise , Cidades , Eliminação de Resíduos Líquidos/instrumentação
15.
Bioresour Technol ; 276: 18-27, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30605835

RESUMO

This study evaluated the performance of two open-photobioreactors operated with microalgae-bacteria (PBR-AB) and purple photosynthetic bacteria (PBR-PPB) consortia during the treatment of diluted (5%) piggery wastewater (PWW) at multiple hydraulic retention times (HRT). At a HRT of 10.6 days, PBR-AB provided the highest removal efficiencies of nitrogen, phosphorus and zinc (87 ±â€¯2, 91 ±â€¯3 and 98 ±â€¯1%), while the highest organic carbon removals were achieved in PBR-PPB (87 ±â€¯4%). The decrease in HRT from 10.6, to 7.6 and 4.1 day caused a gradual deterioration in organic carbon and nitrogen removal, but did not influence the removal of phosphorus and Zn in both photobioreactors. The decrease in HRT caused a severe wash-out of microalgae in PBR-AB and played a key role in the structure of bacterial population in both photobioreactors. In addition, batch biodegradation tests at multiple PWW dilutions (5, 10 and 15%) confirmed the slightly better performance of algal-bacterial systems regardless of PWW dilution.


Assuntos
Bactérias/metabolismo , Microalgas/metabolismo , Águas Residuárias/microbiologia , Biodegradação Ambiental , Nitrogênio/metabolismo , Fósforo/metabolismo , Fotobiorreatores/microbiologia , Zinco/metabolismo
16.
Appl Biochem Biotechnol ; 187(4): 1488-1501, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30259410

RESUMO

This work investigated the cultivation of Chlorella vulgaris in a thin-film flat plate photobioreactor under outdoor conditions and using digested piggery wastewater as the culture medium. The algal cells were able to adapt quickly to the wastewater and outdoor conditions. A specific growth rate of 0.12 day-1 was obtained in the exponential growth phase, which was slightly higher than that during indoor cultivation using artificial culture medium. Results showed that Chlorella vulgaris effectively removed TN, TP, and COD by 72.48%, 86.93%, and 85.94%. Due to the difference in culture conditions and phosphorus availability, the biomass from outdoor cultivation contained higher lipid content and more unsaturated fatty acids compared to indoor cultures, while the amino acid composition was unaffected. Results of metallic element assay indicated that the biomass cultured with wastewater conformed to the standards required for animal feed additive production. The overall cost of the biomass production in the thin-film flat plate photobioreactor (32.94 US$/kg) was estimated to be 4.67 times lower than that of indoor cultivation (154.04 US$/kg). Together, these results provide a basis for large-scale outdoor production of microalgae and wastewater bioremediation.


Assuntos
Microalgas/metabolismo , Nutrientes/isolamento & purificação , Nutrientes/metabolismo , Fotobiorreatores/microbiologia , Águas Residuárias/química , Animais , Biomassa , Técnicas de Cultura , Suínos
17.
Sci Total Environ ; 654: 275-283, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30445327

RESUMO

To convert waste CO2 from flue gases of power plants into value-added products, bio-mitigation technologies show promise. In this study, we cultivated a fast-growing species of green microalgae, Chlorella vulgaris, in different sizes of photobioreactors (PBRs) and developed a strategy using small doses of sugars for enhancing CO2 sequestration under light-emitting diode illumination. Glucose supplementation at low levels resulted in an increase of photoautotrophic growth-driven biomass generation as well as CO2 capture by 10% and its enhancement corresponded to an increase of supplied photon flux. The utilization of urea instead of nitrate as the sole nitrogen source increased photoautotrophic growth by 14%, but change of nitrogen source didn't compromise glucose-induced enhancement of photoautotrophic growth. The optimized biomass productivity achieved was 30.4% higher than the initial productivity of purely photoautotrophic culture. The major pigments in the obtained algal biomass were found comparable to its photoautotrophic counterpart and a high neutral lipids productivity of 516.6 mg/(L·day) was achieved after optimization. A techno-economic model was also developed, indicating that LED-based PBRs represent a feasible strategy for converting CO2 into value-added algal biomass.


Assuntos
Dióxido de Carbono/análise , Sequestro de Carbono , Chlorella vulgaris/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Fotobiorreatores/microbiologia , Açúcares/química , Biomassa , Dióxido de Carbono/metabolismo , Chlorella vulgaris/metabolismo , Estudos de Viabilidade , Microalgas/metabolismo , Modelos Teóricos
18.
Bioresour Technol ; 274: 313-320, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30529478

RESUMO

The aim of this work was to study the performance of pollutants removal and biomass production by co-culture of Chlorella vulgaris and activated sludge in a batch photobioreactor (PBR), compared with their single system to treat a low C/N ratio (COD/N = 4.3) wastewater. The co-culture system surpassed activated sludge system in terms of nutrients removal and outperformed microalgae alone system in regard to COD removal. Biomass productivity of the co-culture system was 343.3 mg L-1 d-1, and the harvested biomass could be developed as biofuels, animal feeds or soil conditioners due to the improved calorific value and cellular composition compared with activated sludge. The low C/N ratio wastewater enabled bacteria to maintain a relatively low level, hence in favor of microalgae enrichment and nutrient recovery.


Assuntos
Biomassa , Carbono/análise , Chlorella vulgaris/metabolismo , Nitrogênio/análise , Fotobiorreatores/microbiologia , Águas Residuárias/química , Animais , Biocombustíveis , Técnicas de Cocultura , Esgotos/microbiologia
19.
Physiol Plant ; 165(3): 476-486, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29345315

RESUMO

The development of high-performance photobioreactors equipped with automatic systems for non-invasive real-time monitoring of cultivation conditions and photosynthetic parameters is a challenge in algae biotechnology. Therefore, we developed a chlorophyll (Chl) fluorescence measuring system for the online recording of the light-induced fluorescence rise and the dark relaxation of the flash-induced fluorescence yield (Qa- - re-oxidation kinetics) in photobioreactors. This system provides automatic measurements in a broad range of Chl concentrations at high frequency of gas-tight sampling, and advanced data analysis. The performance of this new technique was tested on the green microalgae Chlamydomonas reinhardtii subjected to a sulfur deficiency stress and to long-term dark anaerobic conditions. More than thousand fluorescence kinetic curves were recorded and analyzed during aerobic and anaerobic stages of incubation. Lifetime and amplitude values of kinetic components were determined, and their dynamics plotted on heatmaps. Out of these data, stress-sensitive kinetic parameters were specified. This implemented apparatus can therefore be useful for the continuous real-time monitoring of algal photosynthesis in photobioreactors.


Assuntos
Clorofila/metabolismo , Fotobiorreatores/microbiologia , Fotossíntese/fisiologia , Chlamydomonas reinhardtii/metabolismo , Fluorescência , Cinética
20.
J Microbiol Biotechnol ; 28(12): 2019-2028, 2018 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-30394042

RESUMO

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at 200 µmo/m²/s under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.


Assuntos
Clorofíceas/metabolismo , Clorofíceas/efeitos da radiação , Luz , Nitrogênio/metabolismo , Fotobiorreatores/microbiologia , Inanição , Biomassa , Técnicas de Cultura de Células/métodos , Clorofíceas/citologia , Clorofíceas/crescimento & desenvolvimento , Meios de Cultura/química , Relação Dose-Resposta à Radiação , Microalgas/metabolismo , Estimulação Luminosa/métodos , Doses de Radiação , Fatores de Tempo , Xantofilas/biossíntese
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