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1.
Bioresour Technol ; 303: 122940, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32044649

RESUMO

This study aimed to evaluate algal growth, lipid production, and nutrient removal in chicken farm flushing wastewater (CFFW). The excessive ammonia nitrogen (EAN) content in the CFFW wastewater represented a major factor limiting the algal growth. A strategy of mixing CFFW with municipal wastewater (MW) that contained less ammonia nitrogen was adopted. The results showed that the mixed wastewaters reduced ammonia nitrogen content, balanced nutrient profile, and promoted biomass production. The residual nutrients in mixed wastewaters were significantly reduced due to the algal absorption. Furthermore, alga grown on mixed wastewaters accumulated a higher level of total lipids and monounsaturated fatty acids that can be used for biodiesel production. The key issue of low biomass yield of algal grown on CFFW due to the inhibition of EAN was efficiently resolved by mitigating limiting factor to algal growth basing on mixing strategy, and accordingly the nutrients in the wastewater were significantly removed.


Assuntos
Chlorella , Microalgas , Amônia , Animais , Biocombustíveis , Biomassa , Galinhas , Fazendas , Lipídeos , Nitrogênio , Nutrientes , Fósforo , Águas Residuárias
2.
Int J Biol Macromol ; 133: 1090-1101, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054300

RESUMO

The aim of this study is to probe new functions of a polysaccharide from Spirulina platensis (PSP) on constipation and intestinal microbiota in mice. Diphenoxylate-induced constipation in mice was treated with different doses of PSP, followed by examining the defecation patterns, levels of acetyl cholinesterase (AchE), nitric oxide (NO), and tissue section histopathology. The composition of intestinal microbiota was determined by genome sequencing analysis of the 16S rDNA. This study found that the average molecular weight of PSP was 29, 600 Da, and mainly monosaccharides of PSP were rhamnose (24.7%), glucose (16.15%) and galactose (13.32%). The beneficial effects of PSP treatment include defecation improvement, increase of AchE activity, reduction of NO concentration, renovation of the damaged intestinal villus and affection on the expression of some related genes in the constipated mice. In addition, PSP had significant effects on the gut microbiota, showing the enhancement in abundance of beneficial bacteria including Akkermansia, Lactobacillus, Butyricimonas, Candidatus Arthromitus and Prevotella, and the reduction in abundance of harmful bacteria such as Clostridium and Dorea. The present s uncovered a new function of PSP, indicating that PSP could be used in constipation therapies.


Assuntos
Constipação Intestinal/induzido quimicamente , Constipação Intestinal/tratamento farmacológico , Difenoxilato/efeitos adversos , Polissacarídeos Bacterianos/farmacologia , Spirulina/química , Animais , Vilosidades Coriônicas/efeitos dos fármacos , Vilosidades Coriônicas/metabolismo , Constipação Intestinal/metabolismo , Constipação Intestinal/fisiopatologia , Defecação/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Neurotransmissores/metabolismo , Polissacarídeos Bacterianos/uso terapêutico , Água/metabolismo
3.
Int J Mol Sci ; 19(9)2018 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-30227676

RESUMO

The basic leucine-region zipper (bZIP) transcription factors (TFs) act as crucial regulators in various biological processes and stress responses in plants. Currently, bZIP family members and their functions remain elusive in the green unicellular algae Chlamydomonas reinhardtii, an important model organism for molecular investigation with genetic engineering aimed at increasing lipid yields for better biodiesel production. In this study, a total of 17 C. reinhardtii bZIP (CrebZIP) TFs containing typical bZIP structure were identified by a genome-wide analysis. Analysis of the CrebZIP protein physicochemical properties, phylogenetic tree, conserved domain, and secondary structure were conducted. CrebZIP gene structures and their chromosomal assignment were also analyzed. Physiological and photosynthetic characteristics of C. reinhardtii under salt stress were exhibited as lower cell growth and weaker photosynthesis, but increased lipid accumulation. Meanwhile, the expression profiles of six CrebZIP genes were induced to change significantly during salt stress, indicating that certain CrebZIPs may play important roles in mediating photosynthesis and lipid accumulation of microalgae in response to stresses. The present work provided a valuable foundation for functional dissection of CrebZIPs, benefiting the development of better strategies to engineer the regulatory network in microalgae for enhancing biofuel and biomass production.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/genética , Chlamydomonas reinhardtii/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Estresse Salino , Sequência de Aminoácidos , Fatores de Transcrição de Zíper de Leucina Básica/química , Chlamydomonas reinhardtii/química , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/crescimento & desenvolvimento , Metabolismo dos Lipídeos , Fotossíntese , Filogenia , Proteínas de Plantas/química , Conformação Proteica , Domínios Proteicos
4.
Biol Open ; 6(7): 1024-1034, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28679505

RESUMO

As an important oilseed worldwide, Camelina sativa is being increasingly explored for its use in production of food, feed, biofuel and industrial chemicals. However, detailed mechanisms of camelina oil biosynthesis and accumulation, particularly in vegetative tissues, are understood to a very small extent. Here, we present genome-wide identification, cloning and functional analysis of phospholipid diacylglycerol acyltransferase (PDAT) in C. sativa, which catalyses the final acylation step in triacylglycerol (TAG) biosynthesis by transferring a fatty acyl moiety from a phospholipid to diacylglycerol (DAG). We identified five genes (namely CsPDAT1-A, B, and C and CsPDAT2-A and B) encoding PDATs from the camelina genome. CsPDAT1-A is mainly expressed in seeds, whereas CsPDAT1-C preferentially accumulates in flower and leaf tissues. High expression of CsPDAT2-A and CsPDAT2-B was detected in stem and root tissues, respectively. Cold stress induced upregulation of CsPDAT1-A and CsPDAT1-C expression by 3.5- and 2.5-fold, respectively, compared to the control. Salt stress led to an increase in CsPDAT2-B transcripts by 5.1-fold. Drought treatment resulted in an enhancement of CsPDAT2-A mRNAs by twofold and a reduction of CsPDAT2-B expression. Osmotic stress upregulated the expression of CsPDAT1-C by 3.3-fold. Furthermore, the cDNA clones of these CsPDAT genes were isolated for transient expression in tobacco leaves. All five genes showed PDAT enzymatic activity and substantially increased TAG accumulation in the leaves, with CsPDAT1-A showing a higher preference for ɑ-linolenic acid (18:3 ω-3). Overall, this study demonstrated that different members of CsPDAT family contribute to TAG synthesis in different tissues. More importantly, they are involved in different types of stress responses in camelina seedlings, providing new evidence of their roles in oil biosynthesis and regulation in camelina vegetative tissue. The identified CsPDATs may have practical applications in increasing oil accumulation and enhancing stress tolerance in other plants as well.

5.
Bioprocess Biosyst Eng ; 40(7): 1079-1090, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28447169

RESUMO

The CO2 mass transfer model associated with growth kinetics of microalgal biofilm in attached cultivation photobioreactor was developed and verified by using the analysis of pH profiles which were in equilibrium with inorganic carbon components concentrations (CO2, H2CO3, HCO3- and CO32-) in medium. Model simulation results showed that the model well presented the biofilm growth process. The overall volumetric mass transfer coefficient of CO2 was more influenced by CO2 concentration in aerated gas but less by gas aeration rate and medium circulation rate. Other bio-kinetic parameters related with the microalgal biofilm such as CO2 diffusion coefficient in biofilm, Monod maximum utilization rate of CO2, lag phase duration of biofilm and half-saturation CO2 concentration in the biofilm were independent on operational conditions. The pH profiles provided a way to monitor the variations of inorganic carbon concentrations of medium and to regulate the cultivation of attached microalgal biofilm by CO2 supplement.


Assuntos
Fotobiorreatores , Biofilmes , Dióxido de Carbono , Concentração de Íons de Hidrogênio , Microalgas
6.
Biotechnol Lett ; 37(10): 1953-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26063622

RESUMO

OBJECTIVE: Biofilm cultivation of microalgae may be useful for biofuel production. However, many aspects for this cultivation method have not been well assessed. Accordingly, aeration strategy for biofilm cultivation of Scenedesmus dimorphus has been explored. RESULTS: Biomass, lipid and triacylglycerol (TAG) productivity in increased S. dimorphus as the CO2 concentration increased within 0.038-0.5% and kept constant with further increases. The biomass, lipid and TAG productivity increased with the speed increasing and an obvious threshold point was observed at 6.6 ml(-2) min(-1). The lipid and TAG content was unaffected by the aeration rate. CONCLUSIONS: Both the CO2 concentration as well as aeration speed affected the growth of S. dimorphus in biofilm cultivation. The optimized aeration strategy for biofilm cultivation was continuous air flow enriched with 1% CO2 (v/v) at 6.6 ml(-2) min(-1).


Assuntos
Biofilmes/crescimento & desenvolvimento , Scenedesmus/fisiologia , Aerobiose , Dióxido de Carbono/metabolismo , Metabolismo dos Lipídeos , Scenedesmus/crescimento & desenvolvimento , Scenedesmus/metabolismo
7.
Bioresour Technol ; 172: 169-173, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25260180

RESUMO

Making full use of lipid and carbohydrate in microalgae for joint production of biodiesel and bioethanol may create a potential way to cut the high cost of single biofuel production from microalgae. Compared with conventional unicellular oleaginous microalgae, filamentous microalgae Tribonema sp. is richer in lipid and carbohydrate contents and lower protein content, thus, this study explores the suitability of Tribonema sp. as a substrate for joint production of biodiesel and bioethanol. Acid hydrolysis is the key step to saccharify wall cell into fermentable sugar and release lipid. Microalgae biomass (50g/L) was acid (3% H2SO4) hydrolyzed at 121°C for 45min to reach the maximum hydrolysis efficiency (81.48%). Subsequently, the lipid separated with hexane-ethanol from the hydrolysate was converted into microalgae biodiesel and the conversion rate was 98.47%. With yeast Saccharomyces cerevisiae, the maximum ethanol yield of 56.1% was reached from 14.5g/L glucose in hydrolysate.


Assuntos
Biocombustíveis , Microalgas , Biomassa , Etanol/metabolismo , Ácidos Graxos/análise , Fermentação , Hidrólise , Microalgas/química , Saccharomyces cerevisiae/metabolismo
8.
Bioresour Technol ; 127: 216-22, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23131644

RESUMO

The potential of microalgae biofuel has not been realized because of low productivity and high costs associated with the current cultivation systems. In this paper, an attached cultivation method was introduced, in which microalgae cells grew on the surface of vertical artificial supporting material to form algal film. Multiple of the algal films were assembled in an array fashion to dilute solar irradiation to facilitate high photosynthetic efficiency. Results showed that a broad range of microalgae species can grow with this attached method. A biomass productivity of 50-80 g m(-2) d(-1) was obtained outdoors for Scenedesmus obliquus, corresponding to the photosynthetic efficiency of 5.2-8.3% (total solar radiation). This attached method also offers lots of possible advantages over traditional open ponds, such as on water saving, harvesting, contamination controlling and scale-up. The attached cultivation represents a promising technology for economically viable production of microalgae biofuels.


Assuntos
Biofilmes/crescimento & desenvolvimento , Biocombustíveis/microbiologia , Reatores Biológicos , Técnicas de Cultura de Células/métodos , Microalgas/metabolismo , Fotossíntese/fisiologia , Microalgas/crescimento & desenvolvimento , Scenedesmus/crescimento & desenvolvimento , Scenedesmus/metabolismo , Especificidade da Espécie
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