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1.
Insect Sci ; 27(2): 212-223, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30397994

RESUMO

Trehalose-6-phosphate synthase (TPS), an enzyme that hydrolyzes two glucose molecules to yield trehalose, plays a pivotal role in various physiological processes. In this study, we cloned the trehalose-6-phosphate synthase gene (HvTPS) and investigated its expression patterns in various tissues and developmental stages in Heortia vitessoides Moore (Lepidoptera: Crambidae). HvTPS was highly expressed in the fat body and after pupation or before molting. We knocked down TPS in H. vitessoides by RNA interference and found that 3.0 µg of dsHvTPS resulted in optimal interference at 24 h and 36 h post-injection and caused a sharp decline in the survival rate during the 5th instar larval-pupal stage and obviously abnormal or lethal phenotypes. Additionally, compared to the controls, TPS activity and trehalose contents were significantly lower and the glucose content was significantly higher 24 h or 36 h after injection with 3.0 µg of dsHvTPS. Furthermore, the silencing of HvTPS suppressed the expression of six key genes in the chitin biosynthesis pathway and one key gene related to lipid catabolism. The expression levels of two genes associated with lipid biosynthesis were upregulated. These results strongly suggest that HvTPS is essential for the normal growth and development of H. vitessoides and provide a reference for further studies of the utility of key genes involved in chitin and lipid biosynthesis for controlling insect development.


Assuntos
Glucosiltransferases/genética , Mariposas/enzimologia , Animais , Quitina/biossíntese , Larva/metabolismo , Lipídeos/biossíntese , Mariposas/genética , Interferência de RNA , Análise de Sequência de DNA
2.
J Agric Food Chem ; 67(45): 12599-12609, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31644277

RESUMO

In this study, it was found that fulvic acid (FA) enhanced the contents of astaxanthin and lipids in Haematococcus pluvialis under high light and nitrogen starvation conditions by 2- and 1.2-fold, respectively. Meanwhile, the carbohydrate and chlorophyll contents were decreased by FA induction, whereas the levels of reactive oxygen species (ROS) and glutathione (GSH) as well as the expression of astaxanthin and lipid biosynthetic genes were increased. To further explore the interrelation between FA and the biosynthesis of astaxanthin and lipids, a metabolomics analysis of H. pluvialis by combined FA and abiotic stress exposure was conducted by using LC-MS/MS. The contents of some cytoprotective metabolites and signal molecules, including d-maltose, succinate, malic acid, melatonin (MT), and some amino acids, were increased under FA induction and abiotic stress conditions. These metabolites are intermediates in the TCA cycle and Calvin cycle, providing more precursors for the synthesis of astaxanthin and lipids. Moreover, the signal molecules might contribute to enhancing the abiotic stress tolerance. This study provided new insights into the regulatory mechanism of FA on astaxanthin and lipid accumulation in H. pluvialis.


Assuntos
Benzopiranos/metabolismo , Clorofíceas/metabolismo , Lipídeos/biossíntese , Benzopiranos/análise , Clorofíceas/química , Cromatografia Líquida , Lipídeos/química , Melatonina/metabolismo , Metabolômica , Fotossíntese , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Espectrometria de Massas em Tandem , Xantofilas/análise , Xantofilas/biossíntese
3.
World J Microbiol Biotechnol ; 35(10): 157, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31576445

RESUMO

In this study, we aimed to determine the effect of exogenous stress factors (sodium chloride as osmotic stressor, hydrogen peroxide as an inducer of oxidative stress, white light irradiation, and low temperature) on the biosynthesis of carotenoids and lipids by red yeast (Rhodotorula glutinis, R. mucilaginosa, and R. gracilis) during cultivation in media containing potato wastewater and glycerol. According to our results, the yeast were able to grow and biosynthesize lipids and carotenoids in the presence of the applied stress factors. Low temperature caused an increase in the biosynthesis of intracellular lipids and carotenoids. R. gracilis synthesized lipids (21.1 g/100 gd.w.) and carotenoids (360.4 µg/gd.w.) in greater quantities than that of other strains. Under these conditions, there was also an increase in the content of unsaturated fatty acids, especially linoleic and linolenic acids. The highest percentage of polyunsaturated fatty acid (PUFA) (30.4%) was synthesized by the R. gracilis yeast after cultivation at 20°C. Their quantity was 2.5-fold greater than that of the biomass grown in control conditions. The contribution of individual carotenoid fractions depended both on the yeast strain and the culture conditions. Induction of osmotic stress and low temperature intensified the biosynthesis of ß-carotene (up to 73.9% of the total carotenoid content). In oxidative stress conditions, yeast synthesized torulene (up to 82.2%) more efficiently than under other conditions, whereas white light irradiation increased the production of torularhodin (up to 20.0%).


Assuntos
Carotenoides/biossíntese , Meios de Cultura/metabolismo , Lipídeos/biossíntese , Rhodotorula/metabolismo , Meios de Cultura/química , Resíduos Industriais/análise , Rhodotorula/genética , Rhodotorula/crescimento & desenvolvimento
4.
Int J Mol Sci ; 20(18)2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505838

RESUMO

WAX INDUCER1/SHINE1 (WIN1) belongs to the AP2/EREBP transcription factor family and plays an important role in wax and cutin accumulation in plants. Here we show that BnWIN1 from Brassica napus (Bn) has dual functions in wax accumulation and oil synthesis. Overexpression (OE) of BnWIN1 led to enhanced wax accumulation and promoted growth without adverse effects on oil synthesis under salt stress conditions. Lipid profiling revealed that BnWIN1-OE plants accumulated more waxes with elevated C29-alkanes, C31-alkanes, C28-alcohol, and C29-alcohol relative to wild type (WT) under salt stress. Moreover, overexpression of BnWIN1 also increased seed oil content under normal growth conditions. BnWIN1 directly bound to the promoter region of genes encoding biotin carboxyl carrier protein 1 (BCCP1), glycerol-3-phosphate acyltransferase 9 (GPAT9), lysophosphatidic acid acyltransferase 5 (LPAT5), and diacylglycerol acyltransferase 2 (DGAT2) involved in the lipid anabolic process. Overexpression of BnWIN1 resulted in upregulated expression of numerous genes involved in de novo fatty acid synthesis, wax accumulation, and oil production. The results suggest that BnWIN1 is a transcriptional activator to regulate the biosynthesis of both extracellular and intracellular lipids.


Assuntos
Brassica napus/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Lipídeos/biossíntese , Pressão Osmótica , Óleos Vegetais/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Brassica napus/genética , Lipídeos/genética , Proteínas de Plantas/genética , Regiões Promotoras Genéticas/fisiologia , Fatores de Transcrição/genética
5.
J Agric Food Chem ; 67(39): 10984-10993, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31525294

RESUMO

The objective of the present study was to reveal the effects of four types of nitrogen sources (soymeal, yeast extract, KNO3, and ammonium tartrate) on the lipid metabolism of the oleaginous fungus Mortierella alpina using untargeted lipidomics, targeted fatty acid, and reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis. Our results showed clear differences in the contents and compositions of lipids between four types of nitrogen sources. Soymeal and ammonium tartrate supplementation favored the accumulation of triglycerides with arachidonic acid (ARA) and C16-18 fatty acids, respectively. These results were further validated by our targeted fatty acid analysis. RT-qPCR analysis of related genes in M. alpina between the four nitrogen source conditions found that soymeal supplementation dramatically increased the expression of GPAT, ELOVL, and Δ12/Δ6 desaturase. Our findings provided new insights into the regulation of lipid biosynthesis in M. alpina and potential avenues for genetic manipulation and highlighted the importance of an optimal nitrogen source for ARA-rich oil production.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Lipídeos/biossíntese , Lipídeos/química , Espectrometria de Massas/métodos , Mortierella/metabolismo , Nitrogênio/metabolismo , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Ácidos Graxos/biossíntese , Ácidos Graxos/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Mortierella/química , Mortierella/enzimologia , Mortierella/genética
6.
Int J Mol Sci ; 20(18)2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31491935

RESUMO

Palmitoleic acid, one scarce omega-7 monounsaturated fatty acid, has important applications in the fields of medicine and health products. Tribonema has been considered as a promising candidate for the production of palmitoleic acid due to its high lipid and palmitoleic acid content and remarkable heterotrophic ability. The high-density heterotrophic cultivation of Tribonema minus was conducted in this work, and the highest biomass of 42.9 g L-1 and a relatively low lipid content of 28.7% were observed. To further enhance the lipid and palmitoleic acid accumulation, induction strategies under two regimes of phototrophy and heterotrophy with different conditions were investigated and compared. Results demonstrated encouraging promotions both by heterotrophic and phototrophic ways, and the final lipid contents reached 41.9% and 49.0%, respectively. In consideration of the time cost, however, the induction under heterotrophic conditions was much more advantageous, by which the highest lipid and palmitoleic acid productivities of 1.77 g L-1 d-1 and 924 mg L-1 d-1 were obtained respectively, with the lipid yield on glucose of 0.26 g g-1.


Assuntos
Clorófitas/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Fermentação , Lipídeos/biossíntese , Sementes/metabolismo , Metabolismo dos Lipídeos , Processos Fototróficos
7.
Bioresour Technol ; 291: 121834, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31371157

RESUMO

In present study, lipids were extracted from unbroken microalga Chlorella vulgaris with high water content (50% microalgal solution) through three-phase partitioning (TPP). The method was found to extract around 15.9% of total lipid transformable to methyl esters (LTMEs) from unbroken microalgal cells which is two times of Bligh and Dyer method. We investigated the effects of various parameters on TPP performance and were optimised through response surface methodology. The results indicated that incubation duration, temperature and extraction time were positively correlated with LTME extraction efficiency. The optimum temperature was 60 °C, incubation duration was 120 min, extraction time was 60 min, ratio of solvent to DKP was 1:1. The FAME yield was calculated as 12.05% and major fatty acids together accounted for 71.33% which indicated the great potential of the proposed lipid extraction procedure for microalga-based biodiesel production.


Assuntos
Biocombustíveis , Biomassa , Chlorella vulgaris/metabolismo , Lipídeos/isolamento & purificação , Microalgas/metabolismo , Ácidos Graxos/metabolismo , Lipídeos/biossíntese , Solventes , Temperatura Ambiente , Água
8.
Mar Drugs ; 17(8)2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31434347

RESUMO

Microalgal lipids are a source of valuable nutritional ingredients in biotechnological industries, and are precursors to biodiesel production. Here, the effects of salt-induced stresses, including NaCl, KCl, and LiCl stresses, on the production of lipid in green microalga Chlamydomonas reinhardtii (137c) were investigated. NaCl stress dramatically increased saturated fatty acids (SFAs), which accounted for 70.2% of the fatty acid methyl ester (FAMEs) under stress. In contrary, KCl stress led to a slight increase in SFAs (47.05%) with the remaining being polyunsaturated fatty acids (PUFAs) (45.77%). RT-PCR analysis revealed that the genes involved in FA biosynthesis, such as PDH2, ACCase, MAT and KAS2, were up-regulated by NaCl-induced stress. Conversely, the genes responsible for the Kennedy pathway were suppressed. The alteration of FA homeostasis was further assessed by overexpressing MAT, the enzyme responsible for the production of malonyl-ACP, a key building block for FA biosynthesis, in the cyanobacterium Synechococcus elongatus PCC 7942. Intracellular FA composition was affected, with a predominant synthesis of SFAs in transformed cells. Owing to the diversity and relative abundance of SFAs, monounsaturated fatty acid (MUFAs) and PUFAs enable the feasibility of using microorganisms as a source of microalgal lipids or valuable nutritional ingredients; salt-induced stress and expression of MAT are useful in providing precursors for enhanced lipid production.


Assuntos
Chlamydomonas reinhardtii/metabolismo , Chlamydomonas reinhardtii/fisiologia , Lipídeos/biossíntese , Estresse Salino/fisiologia , Chlamydomonas reinhardtii/citologia , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados/metabolismo , Metabolismo dos Lipídeos , Microalgas/metabolismo , Cloreto de Sódio
10.
Nat Chem Biol ; 15(9): 889-899, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31427817

RESUMO

Mycobacterium tuberculosis (Mtb) is the world's most deadly pathogen. Unlike less virulent mycobacteria, Mtb produces 1-tuberculosinyladenosine (1-TbAd), an unusual terpene nucleoside of unknown function. In the present study 1-TbAd has been shown to be a naturally evolved phagolysosome disruptor. 1-TbAd is highly prevalent among patient-derived Mtb strains, where it is among the most abundant lipids produced. Synthesis of TbAd analogs and their testing in cells demonstrate that their biological action is dependent on lipid linkage to the 1-position of adenosine, which creates a strong conjugate base. Furthermore, C20 lipid moieties confer passage through membranes. 1-TbAd selectively accumulates in acidic compartments, where it neutralizes the pH and swells lysosomes, obliterating their multilamellar structure. During macrophage infection, a 1-TbAd biosynthesis gene (Rv3378c) confers marked phagosomal swelling and intraphagosomal inclusions, demonstrating an essential role in regulating the Mtb cellular microenvironment. Although macrophages kill intracellular bacteria through phagosome acidification, Mtb coats itself abundantly with antacid.


Assuntos
Antiácidos/metabolismo , Lipídeos/biossíntese , Lipídeos/química , Mycobacterium tuberculosis/metabolismo , Fagossomos/metabolismo , Animais , Regulação Bacteriana da Expressão Gênica , Humanos , Concentração de Íons de Hidrogênio , Lisossomos , Macrófagos/metabolismo , Camundongos , Estrutura Molecular , Mycobacterium kansasii/genética , Prevalência
11.
Mar Drugs ; 17(8)2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31387272

RESUMO

Enzymes are essential components of biological reactions and play important roles in the scaling and optimization of many industrial processes. Due to the growing commercial demand for new and more efficient enzymes to help further optimize these processes, many studies are now focusing their attention on more renewable and environmentally sustainable sources for the production of these enzymes. Microalgae are very promising from this perspective since they can be cultivated in photobioreactors, allowing the production of high biomass levels in a cost-efficient manner. This is reflected in the increased number of publications in this area, especially in the use of microalgae as a source of novel enzymes. In particular, various microalgal enzymes with different industrial applications (e.g., lipids and biofuel production, healthcare, and bioremediation) have been studied to date, and the modification of enzymatic sequences involved in lipid and carotenoid production has resulted in promising results. However, the entire biosynthetic pathways/systems leading to synthesis of potentially important bioactive compounds have in many cases yet to be fully characterized (e.g., for the synthesis of polyketides). Nonetheless, with recent advances in microalgal genomics and transcriptomic approaches, it is becoming easier to identify sequences encoding targeted enzymes, increasing the likelihood of the identification, heterologous expression, and characterization of these enzymes of interest. This review provides an overview of the state of the art in marine and freshwater microalgal enzymes with potential biotechnological applications and provides future perspectives for this field.


Assuntos
Biotecnologia/métodos , Microalgas/enzimologia , Biodegradação Ambiental , Biocombustíveis , Vias Biossintéticas , Biotecnologia/tendências , Carotenoides/metabolismo , Lipídeos/biossíntese
12.
Bioresour Technol ; 291: 121821, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31352167

RESUMO

The aim of this work was to study ammonium-limited fed-batch conditions in heterotrophic C. vulgaris shake flask cultivations. Therefore, an innovative polymer-based ammonium release technique (polymer beads) was developed. Using these beads in shake flasks, C. vulgaris cultivations resulted in simultaneous growth and lipid accumulation. Lipid productivity was increased by 43% compared to batch cultivations. Furthermore, by online monitoring of the metabolic activity (RAMOS technique), unlimited growth and depletion of nutrients could be identified. A previously unknown sulfur limitation was detected in the applied Bold's Basal Medium. Combining the ammonium release beads with the RAMOS technique proved to be an efficient method for microalgae process development.


Assuntos
Compostos de Amônio/metabolismo , Chlorella vulgaris/metabolismo , Lipídeos/biossíntese , Microalgas/metabolismo , Polímeros/metabolismo
13.
Bioresour Technol ; 291: 121820, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31344639

RESUMO

Mixotrophy (M) assumes sum of autotrophic (A) and heterotrophic (H) growths. In this study, a novel split-mixotrophic cultivation strategy (SMCS) developed as better mixotrophy via offering mutual-benefits through gas-exchange at both headspaces while splitting both trophic modes. To quantify synergistic-growth effects in combined-autotrophy and combined-heterotrophy (CA&CH) of SMCS, gross O2-evolution, DIC and DO concentrations were compared with A, H and M. Average 12-14% and 26-32% increase in DIC and DO concentrations were determined respectively in CA and CH than A, H and M. Biomass yield in CA + CH was increased approx.1.5-folds higher than yields of A + H and M regimes. These results show SMCS as better cultivation strategy than the M by increased biomass and lipid yields. Challenges associated with organic carbon can be solved by SMCS viz. chlorophyll loss, organic carbon uptake inhibition. SMCS could be a breakthrough to integrate bacterial process with algae for better bioprocess economy and energy recovery.


Assuntos
Biomassa , Chlorella/metabolismo , Lipídeos/biossíntese , Processos Autotróficos , Chlorella/crescimento & desenvolvimento , Clorofila/metabolismo , Processos Heterotróficos
14.
Int J Mol Sci ; 20(15)2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31344914

RESUMO

The deregulation of cancer cell metabolic networks is now recognized as one of the hallmarks of cancer. Abnormal lipid synthesis and extracellular lipid uptake are advantageous modifications fueling the needs of uncontrolled cancer cell proliferation. Fatty acids are placed at the crossroads of anabolic and catabolic pathways, as they are implicated in the synthesis of phospholipids and triacylglycerols, or they can undergo ß-oxidation. Key players to these decisions are the long-chain acyl-CoA synthetases, which are enzymes that catalyze the activation of long-chain fatty acids of 12-22 carbons. Importantly, the long-chain acyl-CoA synthetases are deregulated in many types of tumors, providing a rationale for anti-tumor therapeutic opportunities. The purpose of this review is to summarize the last up-to-date findings regarding their role in cancer, and to discuss the related emerging tumor targeting opportunities.


Assuntos
Coenzima A Ligases/metabolismo , Lipídeos/genética , Neoplasias/genética , Animais , Coenzima A Ligases/genética , Humanos , Lipídeos/biossíntese , Neoplasias/enzimologia , Neoplasias/patologia , Fosfolipídeos/biossíntese , Fosfolipídeos/metabolismo , Triglicerídeos/biossíntese , Triglicerídeos/metabolismo
15.
BMC Biotechnol ; 19(1): 53, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31349823

RESUMO

BACKGROUND: Increasing CO2 emissions have resulted in ocean acidification, affecting marine plant photosynthesis and changing the nutrient composition of marine ecosystems. The physiological and biochemical processes of marine phytoplankton in response to ocean acidification have been reported, but have been mainly focused on growth and photosynthetic physiology. To acquire a thorough knowledge of the molecular regulation mechanisms, model species with clear genetic background should be selected for systematic study. Phaeodactylum tricornutum is a pennate diatom with the characteristics of small genome size, short generation cycle, and easy to transform. Furthermore, the genome of P. tricornutum has been completely sequenced. RESULTS AND DISCUSSION: In this study, P. tricornutum was cultured at high and normal CO2 concentrations. Cell composition changes during culture time were investigated. The 13C isotope tracing technique was used to determine fractional labeling enrichments for the main cellular components. The results suggested that when lipid content increased significantly under high CO2 conditions, total protein and soluble sugar contents decreased. The 13C labeling experiment indicated that the C skeleton needed for fatty acid C chain elongation in lipid synthesis under high CO2 conditions is not mainly derived from NaHCO3 (carbon fixed by photosynthesis). CONCLUSION: This study indicated that breakdown of intracellular protein and soluble sugar provide C skeleton for lipid synthesis under high CO2 concentration.


Assuntos
Proteínas de Algas/metabolismo , Dióxido de Carbono/metabolismo , Carbono/metabolismo , Diatomáceas/metabolismo , Lipídeos/biossíntese , Açúcares/metabolismo , Isótopos de Carbono/metabolismo , Diatomáceas/genética , Diatomáceas/fisiologia , Ecossistema , Concentração de Íons de Hidrogênio , Espaço Intracelular/metabolismo , Lipogênese , Oceanos e Mares , Fotossíntese , Água do Mar/química , Solubilidade , Açúcares/química
16.
Bioprocess Biosyst Eng ; 42(9): 1409-1419, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31321529

RESUMO

Microbial biomass which mostly generated from the microbial processes of bacteria, yeasts, and microalgae is an important resource. Recent concerns in microbial biomass production field, especially microbial lipid production for biofuel, have been focused towards the mixed culture of microalgae and yeast. To more comprehensive understanding of the mixed culture for microbial biomass, mono Chlorella pyrenoidosa, mono Yarrowia lipolytica and the mixed culture were investigated in the present work. Results showed that the mixed culture achieved significantly faster cell propagation of microalga and yeast, smaller individual cell size of yeast and higher relative chlorophyll content of microalga. The mixed culture facilitated the assimilation of carbon and nitrogen and drove the carbon flow to carbohydrate. Besides higher lipid yield (0.77 g/L), higher yields of carbohydrates (1.82 g/L), protein (1.99 g/L) and heating value (114.64 kJ/L) indicated the microbial biomass harvested from the mixed culture have more potential utilization in renewable energy, feedstuff, and chemical industry.


Assuntos
Biomassa , Chlorella/crescimento & desenvolvimento , Lipídeos/biossíntese , Microalgas/crescimento & desenvolvimento , Yarrowia/crescimento & desenvolvimento
17.
Bioresour Technol ; 289: 121717, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31279322

RESUMO

To enhance biodiesel production and quality from a bloom-forming diatom Skeletonema costatum, a two-stage model, in which cells were cultured in nutrient replete conditions first and then transferred to nutrient limitation conditions, was explored. Compared to one-stage model, nutrient limitation in the second stage significantly increased lipid content in spite of decreasing growth; consequently, Si-limitation and N-Si-limitation respectively increased lipid productivity by 37.6% and 76.7% for 6 h induction, and 42.8% and 113.7% for 12 induction. Nutrient limitation enhanced the proportions of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) but reduced polyunsaturated fatty acid (PUFA). Therefore, N-Si-limitation reduced iodine value by 33.7% and 45.6% but increased cetane number by 6.4% and 21.6% for 6 and 24 h induction, respectively. These findings indicate that the two-stage model with N-Si-limitation can enhance lipid productivity as well as biodiesel quality from diatoms.


Assuntos
Biocombustíveis , Diatomáceas/metabolismo , Lipídeos/biossíntese , Nitrogênio/farmacologia , Silício/farmacologia , Diatomáceas/efeitos dos fármacos , Diatomáceas/crescimento & desenvolvimento
18.
Bioresour Technol ; 289: 121682, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31271918

RESUMO

Microalgal biomass is considered as the most promising feedstock for sustainable production of liquid fuels. Lipid production with Microchloropsis salina was studied in open thin-layer cascade (TLC) photobioreactors with a surface area of 8 m2 applying a physically simulated Mediterranean summer climate. High lipid concentrations of up to 6.6 g L-1 with 46% (w w-1) total lipids in dry cell mass were achieved in two-phase batch processes applying a nitrogen limitation. The two-phase batch process was transferred into a continuously operated reactor cascade of two TLC photobioreactors. Microchloropsis salina cells were produced continuously in the first photobioreactor, whereas continuous lipid production was enabled in the second, nitrogen-limited TLC photobioreactor resulting in continuous production of 3.0 g L-1 lipids with a high overall lipid space-time-yield of 0.2 g L-1 d-1. The control of alkalinity to about 10 mM resulted in high CO2 conversion efficiencies of 84-87%.


Assuntos
Lipídeos/biossíntese , Microalgas/metabolismo , Biomassa , Nitrogênio/metabolismo , Fotobiorreatores
19.
J Appl Microbiol ; 127(5): 1442-1453, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31325223

RESUMO

AIMS: The aim of this study was to elucidate the chemical properties and applications of trehalose lipids produced by Rhodococcus qingshengii strain FF and optimize its production yield. METHODS AND RESULTS: Strain FF was identified as R. qingshengii. It was observed to produce biosurfactants in the presence of n-hexadecane. The biosurfactants were identified as the mixture of trehalose triesters and trehalose tetraesters, mainly consisting of TrehC12 C3 C6 C12 :10, TrehC11 C8 C6 :6, TrehC11 C6 C4 :5 and TrehC6 C4 C6 :5 based on the analysis of thin layer chromatography, Fourier transform infrared and flight tandem mass spectrometry. The best carbon source and nitrogen source for producing trehalose lipids was the mixture of n-hexadecane and oleic acid (m : m = 1 : 1) and the organic nitrogen, urea. Under this condition, the production of trehalose lipids could reach 7·97 g l-1 . The crude trehalose lipids showed extremely high surface-active properties and were proven to promote the degradation of naphthalene. CONCLUSIONS: The trehalose lipids produced by R. qingshengii strain FF exhibited high surfactant activity under various conditions and were proven to promote the degradation of naphthalene. SIGNIFICANCE AND IMPACT OF THE STUDY: Rhodococcus qingshengii strain FF is a potential candidate for bioremediation. The trehalose lipids might be used as unique biosurfactants in cosmetic industries, biological formulations and other applications.


Assuntos
Lipídeos/química , Rhodococcus/metabolismo , Trealose/análise , Trealose/metabolismo , Alcanos/metabolismo , Cromatografia em Camada Delgada , Microbiologia Ambiental , Lipídeos/biossíntese , Filogenia , Rhodococcus/classificação , Rhodococcus/genética , Rhodococcus/isolamento & purificação , Tensoativos/química , Tensoativos/metabolismo , Espectrometria de Massas em Tandem , Águas Residuárias/microbiologia
20.
World J Microbiol Biotechnol ; 35(7): 110, 2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31280381

RESUMO

Carbon sources whether types or magnitudes were fateful in terms of stimulating growth and lipids accumulation in microalgae applied for biodiesel production. The set scenario of this work was to investigate the feasibilities of glucose (G) combining with sodium acetate (SA) carbon sources in enhancing biomass and lipid accumulation in Coccomyxa subellipsoidea. The results demonstrated that C. subellipsoidea subjected to the combination feeding of G (20 g/L) and SA (12 g/L) achieved the favorable biomass (5.22 g/L) and lipid content (52.16%). The resulting lipid productivity (388.96 mg/L/day) was 1.33- to 7.60-fold more than those of sole G or SA as well as other combinations of G and SA. Even though the total fatty acids of C. subellipsoidea cells treated with the optimal combination of G and SA showed no noticeable increment in comparison with sole G or SA, the proportion of monounsaturated C18:1 (over 48.69%) and the content of C18:3 (< 12%) were commendable in high-quality algal biodiesel production. Further, such fascinating lipid accumulation in C. subellipsoidea cells treated with G combining with SA might be attributed to that G promoted glycolysis as well as SA activated glyoxylate shunt and TCA cycle to synergistically provide sufficient acetyl-CoA precursors for lipid accumulation. These findings hinted the potential of the combination of carbon sources in enhancing the overall lipid productivity to offset alga-based biodiesel production cost and would guide other alga strains cultivation.


Assuntos
Clorófitas/crescimento & desenvolvimento , Clorófitas/metabolismo , Glucose/metabolismo , Lipídeos/biossíntese , Acetato de Sódio/metabolismo , Biocombustíveis , Biomassa , Carbono/metabolismo , Clorófitas/citologia , Meios de Cultura/química , Ácidos Graxos/biossíntese , Metabolômica , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Nitrogênio/metabolismo
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