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1.
J Food Sci ; 87(11): 5029-5041, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36193550

RESUMO

The purpose of this study is to evaluate the effect of high hydrostatic pressure (HHP) as a novel approach for yeast cell disruption and lipid extraction from Lipomyces starkeyi DSM 70295 grown in glucose medium (40 g/L and C/N:55/1) at initial pH of 5.0, 25°C, and 130 rpm for 8 days. HHP extraction conditions including pressure, time, and temperature were optimized by response surface methodology. The high speed homogenizer-assisted extraction (HSH) was also used for comparison. The biomass subjected to HHP was examined under scanning electron microscopy and light microscope. A maximal lipid yield of 45.8 ± 2.1% in dry cell basis (w/w) was achieved at 200 MPa, 40°C, and 15 min, while a minimum yield of 15.2 ± 0.9% was observed at 300 MPa, 40°C, and 10 min (p < 0.05). The lipid yield decreased with increasing pressure. It was demonstrated that low pressure (200 MPa) collapsed the cells, while high pressure (400 MPa) created protrusions on the cell wall and cell fragments spread in the environment. This study favors HHP as a promising method for Lipomyces oil extraction. PRACTICAL APPLICATION: Single-cell oils are considered future alternatives to plant-based oils as food additives and dietary supplements. Oleaginous microorganisms accumulate oils in their cell plasma, which makes extraction essential. One of the main obstacles with existing methods is the utilization of strong acids to destroy cell walls. This study aims to demonstrate high hydrostatic pressure as a rapid method for lipid extraction from oleaginous yeast Lipomyces starkeyi.


Assuntos
Lipomyces , Lipomyces/metabolismo , Biomassa , Pressão Hidrostática , Óleos , Leveduras/metabolismo
2.
J Biotechnol ; 358: 46-54, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36041515

RESUMO

The oleaginous yeast Lipomyces starkeyi is expected to be a new lipid source since this microorganism is capable of accumulating more than 85% lipid per dry cell weight. For effective utilization of oleaginous yeast, mutants with improved lipid production compared to the wild-type have been screened by methods such as single-cell sorting and Percoll density gradient centrifugation. Because these methods need to reculture all mutated oleaginous yeasts together in a flask, it is difficult to evaluate the growth of each individual mutant. Thus, screening for the slow-growing mutants with high-throughput has never been performed by conventional methods. In this study, we developed a high-throughput method using gel microdroplets (GMD). With this method, the growth and lipid production of L. starkeyi can be evaluated simultaneously. L. starkeyi grew in GMD and the size of these microcolonies was evaluated by scattered light. Finally, a mutant with a 10-fold delay in growth compared to the wild-type was obtained. Analysis of genetic information in this mutant could reveal valuable information about critical genes involved in the growth of these microorganisms, which could then be utilized further.


Assuntos
Ensaios de Triagem em Larga Escala , Lipomyces , Lipídeos , Lipomyces/genética , Leveduras
3.
J Cell Sci ; 135(16)2022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35833504

RESUMO

Lipid droplets are cytoplasmic organelles that store lipids for energy and membrane synthesis. The oleaginous yeast Lipomyces starkeyi is one of the most promising lipid producers and has attracted attention as a biofuel source. It is known that the expansion of lipid droplets is enhanced under nutrient-poor conditions. Therefore, we prepared a novel nitrogen-depleted medium (N medium) in which to culture L. starkeyi cells. Lipid accumulation was rapidly induced, and this was reversed by the addition of ammonium. In this condition, cell proliferation stopped, and cells with giant lipid droplets were arrested in G1 phase. We investigated whether cell cycle arrest at a specific phase is required for lipid accumulation. Lipid accumulation was repressed in hydroxyurea-synchronized S phase cells and was increased in nocodazole-arrested G2/M phase cells. Moreover, the enrichment of G1 phase cells seen upon rapamycin treatment induced massive lipid accumulation. From these results, we conclude that L. starkeyi cells store lipids from G2/M phase and then arrest cell proliferation in the subsequent G1 phase, where lipid accumulation is enhanced. Cell cycle control is an attractive approach for biofuel production.


Assuntos
Biocombustíveis , Lipomyces , Pontos de Checagem da Fase G1 do Ciclo Celular , Lipídeos , Lipomyces/metabolismo , Leveduras
4.
Appl Microbiol Biotechnol ; 106(17): 5629-5642, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35906440

RESUMO

Oleaginous yeasts have received significant attention due to their substantial lipid storage capability. The accumulated lipids can be utilized directly or processed into various bioproducts and biofuels. Lipomyces starkeyi is an oleaginous yeast capable of using multiple plant-based sugars, such as glucose, xylose, and cellobiose. It is, however, a relatively unexplored yeast due to limited knowledge about its physiology. In this study, we have evaluated the growth of L. starkeyi on different sugars and performed transcriptomic and metabolomic analyses to understand the underlying mechanisms of sugar metabolism. Principal component analysis showed clear differences resulting from growth on different sugars. We have further reported various metabolic pathways activated during growth on these sugars. We also observed non-specific regulation in L. starkeyi and have updated the gene annotations for the NRRL Y-11557 strain. This analysis provides a foundation for understanding the metabolism of these plant-based sugars and potentially valuable information to guide the metabolic engineering of L. starkeyi to produce bioproducts and biofuels. KEY POINTS: • L. starkeyi metabolism reprograms for consumption of different plant-based sugars. • Non-specific regulation was observed during growth on cellobiose. • L. starkeyi secretes ß-glucosidases for extracellular hydrolysis of cellobiose.


Assuntos
Biocombustíveis , Celobiose , Lipídeos , Lipomyces , Açúcares , Leveduras
5.
Bioresour Technol ; 344(Pt B): 126294, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34748983

RESUMO

The enhanced production of microbial lipids suitable for manufacturing biodiesel from oleaginous yeast Lipomyces starkeyi is critically reviewed. Recent advances in several aspects involving the biosynthetic pathways of lipids, current conversion efficiencies using various carbon sources, intensification strategies for improving lipid yield and productivity in L. starkeyi fermentation, and lipid extraction approaches are analyzed from about 100 papers for the past decade. Key findings on strategies are summarized, including (1) optimization of parameters, (2) cascading two-stage systems, (3) metabolic engineering strategies, (4) mutagenesis followed by selection, and (5) co-cultivation of yeast and algae. The current technical limitations are analyzed. Research suggestions like examination of more gene targets via metabolic engineering are proposed. This is the first comprehensive review on the latest technical advances in strategies from the perspective of process and metabolic engineering to further increase the lipid yield and productivity from L. starkeyi fermentation.


Assuntos
Biocombustíveis , Lipomyces , Fermentação , Lipídeos
6.
Biotechnol J ; 16(11): e2100238, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34418308

RESUMO

Simultaneous co-fermentation of glucose and xylose is a key desired trait of engineered Saccharomyces cerevisiae for efficient and rapid production of biofuels and chemicals. However, glucose strongly inhibits xylose transport by endogenous hexose transporters of S. cerevisiae. We identified structurally distant sugar transporters (Lipomyces starkeyi LST1_205437 and Arabidopsis thaliana AtSWEET7) capable of co-transporting glucose and xylose from previously unexplored oleaginous yeasts and plants. Kinetic analysis showed that LST1_205437 had lenient glucose inhibition on xylose transport and AtSWEET7 transported glucose and xylose simultaneously with no inhibition. Modelling studies of LST1_205437 revealed that Ala335 residue at sugar binding site can accommodates both glucose and xylose. Docking studies with AtSWEET7 revealed that Trp59, Trp183, Asn145, and Asn179 residues stabilized the interactions with sugars, allowing both xylose and glucose to be co-transported. In addition, we altered sugar preference of LST1_205437 by single amino acid mutation at Asn365. Our findings provide a new mechanistic insight on glucose and xylose transport mechanism of sugar transporters and the identified sugar transporters can be employed to develop engineered yeast strains for producing cellulosic biofuels and chemicals.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/enzimologia , Glucose , Lipomyces/enzimologia , Proteínas de Transporte de Monossacarídeos/genética , Xilose , Arabidopsis/genética , Fermentação , Cinética , Lipomyces/genética , Saccharomyces cerevisiae/genética
7.
Genes Cells ; 26(8): 627-635, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34085353

RESUMO

Emerging evidence implicates the vital role of mitochondria in lipid consumption and storage, highlighting the intimate link between energy production and saving. Although formation of giant lipid droplets, which is the key hallmark of the oleaginous yeast Lipomyces starkeyi, appears to be regulated in response to changes in mitochondrial shape and metabolism, technical limitations of genetic manipulation have become an obstacle to uncover the mitochondrial behavior in this nonconventional yeast. Here, we established an L. starkeyi strain stably expressing a fluorescent marker for monitoring mitochondrial morphology and degradation and found that mitochondria are mostly fragmented in L. starkeyi cells under fermentable, nonfermentable, and nitrogen depletion conditions. Notably, a fraction of mitochondria-specific fluorescent signals was localized to the vacuole, a lytic organelle in yeast, indicating degradation of mitochondria in those cells. This possible catabolic event was more predominant in cells under nutrient-poor conditions than that in cells under nutrient-rich conditions, concomitantly with lipid droplet formation. Collectively, our studies provide a new tool to investigate mitochondrial dynamics in L. starkeyi and decipher the potential role of mitochondrial degradation in lipid metabolism.


Assuntos
Lipomyces/metabolismo , Dinâmica Mitocondrial , Fermentação , Metabolismo dos Lipídeos , Nitrogênio/deficiência , Nitrogênio/metabolismo , Vacúolos/metabolismo
8.
ACS Synth Biol ; 10(5): 1000-1008, 2021 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-33915043

RESUMO

Oleaginous yeast, such as Lipomyces starkeyi, are logical organisms for production of higher energy density molecules like lipids and terpenes. We demonstrate that transgenic L. starkeyi strains expressing an α-zingiberene synthase gene from lemon basil or Hall's panicgrass can produce up to 17 mg/L α-zingiberene in yeast extract peptone dextrose (YPD) medium containing 4% glucose. The transgenic strain was further examined in 8% glucose media with C/N ratios of 20 or 100, and YPD. YPD medium resulted in 59 mg/L α-zingiberene accumulation. Overexpression of selected genes from the mevalonate pathway achieved 145% improvement in α-zingiberene synthesis. Optimization of the growth medium for α-zingiberene production led to 15% higher titer than YPD medium. The final transgenic strain produced 700 mg/L α-zingiberene in fed-batch bioreactor culture. This study opens a new synthetic route to produce α-zingiberene or other terpenoids in L. starkeyi and establishes this yeast as a platform for jet fuel biosynthesis.


Assuntos
Engenharia Genética/métodos , Lipomyces/genética , Lipomyces/metabolismo , Sesquiterpenos Monocíclicos/metabolismo , Técnicas de Cultura Celular por Lotes/métodos , Reatores Biológicos , Meios de Cultura/química , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos , Glucose/metabolismo , Hidrocarbonetos/metabolismo , Lipídeos/biossíntese , Lipomyces/crescimento & desenvolvimento , Ácido Mevalônico/metabolismo , Microrganismos Geneticamente Modificados , Ocimum basilicum/enzimologia , Ocimum basilicum/genética , Panicum/enzimologia , Panicum/genética , Transdução de Sinais/genética , Transgenes
9.
Adv Exp Med Biol ; 1261: 153-163, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33783737

RESUMO

Oleaginous yeasts, Yarrowia lipolytica and Lipomyces starkeyi, can synthesize more than 20% of lipids per dry cell weight from a wide variety of substrates. This feature is attractive for cost-efficient production of industrial biodiesel fuel. These yeasts are also very promising hosts for the efficient production of more value-added lipophilic compound carotenoids, e.g., lycopene and astaxanthin, although they cannot naturally biosynthesize carotenoids. Here, we review recent progress in researches on carotenoid production by oleaginous yeasts, which include red yeasts that naturally produce carotenoids, e.g., Rhodotorula glutinis and Xanthophyllomyces dendrorhous. Our new results on pathway engineering of L. starkeyi for lycopene production are also revealed in the present review.


Assuntos
Lipomyces , Basidiomycota , Carotenoides , Rhodotorula , Leveduras/genética
10.
J Biosci Bioeng ; 131(6): 613-621, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33582014

RESUMO

The oleaginous yeast Lipomyces starkeyi is an intriguing lipid producer that can produce triacylglycerol (TAG), a feedstock for biodiesel production. We previously reported that the L. starkeyi mutant E15 with high levels of TAG production compared with the wild-type was efficiently obtained using Percoll density gradient centrifugation. However, considering its use for biodiesel production, it is necessary to further improve the lipid productivity of the mutant. In this study, we aimed to obtain mutants with better lipid productivity than E15, evaluate its lipid productivity, and analyze lipid synthesis-related gene expression in the wild-type and mutant strains. The mutants E15-11, E15-15, and E15-25 exhibiting higher lipid productivity than E15 were efficiently isolated from cells exposed to ultraviolet light using Percoll density gradient centrifugation. They exhibited approximately 4.5-fold higher lipid productivity than the wild-type on day 3. The obtained mutants did not exhibit significantly different fatty acid profiles than the wild-type and E15 mutant strains. E15-11, E15-15, and E15-25 exhibited higher expression of acyl-CoA synthesis- and Kennedy pathway-related genes than the wild-type and E15 mutant strains. Activation of the pentose phosphate pathway, which supplies NADPH, was also observed. These results suggested that the increased expression of acyl-CoA synthesis- and Kennedy pathway-related genes plays a vital role in lipid productivity in the oleaginous yeast L. starkeyi.


Assuntos
Lipídeos/biossíntese , Lipomyces , Raios Ultravioleta , Biocombustíveis , Ácidos Graxos/metabolismo , Regulação Fúngica da Expressão Gênica/efeitos da radiação , Metabolismo dos Lipídeos/genética , Metabolismo dos Lipídeos/efeitos da radiação , Lipídeos/efeitos da radiação , Lipomyces/genética , Lipomyces/isolamento & purificação , Lipomyces/metabolismo , Lipomyces/efeitos da radiação , Engenharia Metabólica , Organismos Geneticamente Modificados , Via de Pentose Fosfato/genética , Via de Pentose Fosfato/efeitos da radiação , Triglicerídeos/metabolismo , Leveduras/genética , Leveduras/metabolismo , Leveduras/efeitos da radiação
11.
Biotechnol Lett ; 43(5): 967-979, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33517513

RESUMO

OBJECTIVE: The extraction of the hemicellulose fraction of sugarcane bagasse (SCB) by acid hydrolysis was evaluated in an autoclave and a Parr reactor aiming the application of the hydrolysate as a carbon source for lipid production by Lipomyces starkeyi. RESULTS: The hydrolysis that resulted in the highest sugar concentration was obtained by treatment in the Parr reactor (HHR) at 1.5% (m/v) H2SO4 and 120 °C for 20 min, reaching a hemicellulose conversion of approximately 82%. The adaptation of the yeast to the hydrolysate provided good fermentability and no lag phase. The fermentation of hemicellulose-derived sugars (HHR) by L. starkeyi resulted in a 27.8% (w/w) lipid content and YP/S of 0.16 g/l.h. Increasing the inoculum size increased the lipid content by approximately 61%, reaching 44.8% (w/w). CONCLUSION: The hemicellulose hydrolysate from SCB is a potential substrate for L. starkeyi to produce lipids for biodiesel synthesis based on the biorefinery concept.


Assuntos
Lipomyces/metabolismo , Óleos/metabolismo , Polissacarídeos/química , Saccharum/química , Adaptação Fisiológica , Biocombustíveis , Reatores Biológicos , Celulose/química , Celulose/metabolismo , Fermentação , Temperatura Alta , Hidrólise , Lipídeos/biossíntese , Lipomyces/crescimento & desenvolvimento , Polissacarídeos/metabolismo , Açúcares/química , Açúcares/metabolismo , Ácidos Sulfúricos/química
12.
Bioresour Technol ; 325: 124635, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33461125

RESUMO

Giant reed (Arundo donax L.) is a promising source of carbohydrates that can be converted into single cell oil (SCO) by oleaginous yeasts. Microbial conversion of both hemicellulose and cellulose fractions represents the key step for increasing the economic sustainability for SCO production. Lipomyces starkeyi DSM 70,296 was cultivated in two xylose-rich hydrolysates, obtained by the microwave-assisted hydrolysis of hemicellulose catalysed by FeCl3 or Amberlyst-70, and in two glucose-rich hydrolysates obtained by the enzymatic hydrolysis of cellulose. L. starkeyi grew on both undetoxified and partially-detoxified hydrolysates, achieving the lipid content of 30 wt% and yield values in the range 15-24 wt%. For both integrated cascade processes the final production of about 8 g SCO from 100 g biomass was achieved. SCO production through integrated hydrolysis cascade processes represents a promising solution for the effective exploitation of lignocellulosic feedstock from perennial grasses towards new generation biodiesel and other valuable bio-based products.


Assuntos
Lipomyces , Fermentação , Poaceae , Xilose
13.
Chemosphere ; 269: 129390, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33385663

RESUMO

This work focuses on the lime pretreatment of rice straw, agricultural waste in northeast Vietnam, for microbial lipid (bio-lipid) production. A response surface methodology approach was performed to optimize parameters for the pretreatment process. These parameters are the concentration of Ca(OH)2, hydrolysis temperature, and maintained time; the effect is considered bio-lipid production yield. The lipid yield was estimated through consolidated bioprocessing of the pretreated rice straw as a substrate and using the fungus strain (Aspergillus oryzae 32) and the yeast strain (Lipomyces starkeyi 22). As a result, the optimal pretreatment conditions for maximum lipid yield were obtained at Ca(OH)2 concentration of 12 g/L and hydrolysis temperature of 110 °C within 60 min. The accumulated lipid in fermentation using these oleaginous microorganisms was 8.5g/100g oven-dry weight of rice straw (10.9g/100g for pretreated rice straw). The biolipid consisted of 42.6% saturated, 21.1% monounsaturated (MUFA), and 35.1% polyunsaturated (PUFA) fatty acids.


Assuntos
Oryza , Compostos de Cálcio , Fermentação , Hidrólise , Lipomyces , Óxidos , Vietnã
14.
Yeast ; 38(12): 625-633, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34596906

RESUMO

The oleaginous yeast Lipomyces starkeyi is a powerful lipid producer with great industrial potential. Recent studies have reported the isolation of mutant L. starkeyi cells with higher lipid producing capacity. Although genetic engineering strategies have been applied to L. starkeyi, classical genetic approaches are lacking. The development of tools that facilitate genetic crosses in L. starkeyi would not only make it possible to build improved lipid-producing strains but also facilitate molecular biological analysis of this species. In this study, I report a set of strains and approaches useful for performing genetic crosses with L. starkeyi. The homothallic L. starkeyi reportedly forms an ascus containing two to 20 spores. These spores were resistant to glusulase and could be dissected using a micromanipulator, suggesting that random spore and tetrad (spore dissection) analysis can be adapted for L. starkeyi. Additionally, to isolate a pair of heterothallic strains useful for genetic crosses, the homothallic strain was exposed to UV irradiation, and 10 self-sterile strains were crossed with one another. One of these combinations, Ls75 and Ls100, sporulated stably. Moreover, to detect genetic recombination, I introduced a different drug resistance marker into each strain and crossed them. The resulting progeny exhibited Mendelian segregation of the resistance markers. Altogether, the work reported here provides a powerful resource for genetic analysis in L. starkeyi.


Assuntos
Lipomyces , Cruzamentos Genéticos , Engenharia Genética , Lipomyces/genética , Leveduras
15.
Curr Opin Biotechnol ; 67: 15-25, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33246131

RESUMO

Xylose is the second most abundant sugar in lignocellulosic biomass. Efficient and rapid xylose utilization is essential for the economic bioconversion of lignocellulosic biomass into value-added products. Building on previous pathway engineering efforts to enable xylose fermentation in Saccharomyces cerevisiae, recent work has focused on reprogramming regulatory networks to enhance xylose utilization by engineered S. cerevisiae. Also, potential benefits of using xylose for the production of various value-added products have been demonstrated. With increasing needs of lipid-derived bioproducts, activation and enhancement of xylose metabolism in oleaginous yeasts have been attempted. This review highlights recent progress of metabolic engineering to achieve efficient and rapid xylose utilization by S. cerevisiae and oleaginous yeasts, such as Yarrowia lipolytica, Rhodosporidium toruloides, and Lipomyces starkeyi.


Assuntos
Biocombustíveis , Xilose , Fermentação , Lipomyces , Engenharia Metabólica , Rhodotorula , Saccharomyces cerevisiae/genética
16.
Microb Cell Fact ; 19(1): 204, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33167962

RESUMO

BACKGROUND: Lipids from oleaginous yeasts emerged as a sustainable alternative to vegetable oils and animal fat to produce biodiesel, the biodegradable and environmentally friendly counterpart of petro-diesel fuel. To develop economically viable microbial processes, the use of residual feedstocks as growth and production substrates is required. RESULTS: In this work we investigated sugar beet pulp (SBP) and molasses, the main residues of sugar beet processing, as sustainable substrates for the growth and lipid accumulation by the oleaginous yeast Lipomyces starkeyi. We observed that in hydrolysed SBP the yeast cultures reached a limited biomass, cellular lipid content, lipid production and yield (2.5 g/L, 19.2%, 0.5 g/L and 0.08 g/g, respectively). To increase the initial sugar availability, cells were grown in SBP blended with molasses. Under batch cultivation, the cellular lipid content was more than doubled (47.2%) in the presence of 6% molasses. Under pulsed-feeding cultivation, final biomass, cellular lipid content, lipid production and lipid yield were further improved, reaching respectively 20.5 g/L, 49.2%, 9.7 g/L and 0.178 g/g. Finally, we observed that SBP can be used instead of ammonium sulphate to fulfil yeasts nitrogen requirement in molasses-based media for microbial oil production. CONCLUSIONS: This study demonstrates for the first time that SBP and molasses can be blended to create a feedstock for the sustainable production of lipids by L. starkeyi. The data obtained pave the way to further improve lipid production by designing a fed-batch process in bioreactor.


Assuntos
Beta vulgaris/metabolismo , Biocombustíveis , Lipídeos/biossíntese , Lipomyces/metabolismo , Biomassa , Reatores Biológicos , Meios de Cultura/química , Hidrólise , Lipomyces/crescimento & desenvolvimento , Melaço
17.
Int J Biol Macromol ; 165(Pt B): 1656-1663, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33091476

RESUMO

In order to increase content of glucuronic acid in the exopolysaccharide (EPS) and its flocculating activity, an UDP-glucose dehydrogenase gene was overexpressed in Lipomyces starkeyi V19. The obtained U9 strain could produce 62.1 ± 1.2 g/l EPS while the V19 strain only produced 53.5 ± 1.3 g/l EPS. The compositions of monosaccharides (mannose, glucuronic acid and galactose) in the purified EPS (U9-EPS) from the U9 strain contained 3.79:1:5.52 while those in the purified EPS (V19-EPS) were 3.94:1:6.29. The flocculation rate of the U9-EPS on kaolin clay reached 87.9%, which was significantly higher than that (74.7%) of the V19-EPS while the decolorization rate of Congo Red (CR) by the U9-EPS reached 94.3%, which was significantly higher than that of CR by the V19-EPS (86.23%). The results showed that the purified bioflocculant U9-EPS had effective flocculation of kaolin clay. The U9-EPS also had high ability to flocculate the polluted river water and decolorize Congo red.


Assuntos
Lipomyces/enzimologia , Polissacarídeos/biossíntese , Uridina Difosfato Glucose Desidrogenase/genética , Técnicas de Cultura Celular por Lotes , Biomassa , Fermentação , Floculação , Liofilização , Caulim/química , Lipomyces/citologia , Polissacarídeos/isolamento & purificação , Padrões de Referência , Fatores de Tempo , Transformação Genética , Uridina Difosfato Glucose Desidrogenase/metabolismo , Poluentes Químicos da Água/análise , Poluição da Água
18.
Bioresour Technol ; 315: 123790, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32707500

RESUMO

Single cell oil (SCO) represents an outstanding alternative to both fossil sources and vegetable oils from food crops waste. In this work, an innovative two-step process for the conversion of cellulosic paper mill waste into SCO was proposed and optimised. Hydrolysates containing glucose and xylose were produced by enzymatic hydrolysis of the untreated waste. Under the optimised reaction conditions (Cellic® CTec2 25 FPU/g glucan, 48 h, biomass loading 20 g/L), glucose and xylose yields of 95 mol% were reached. The undetoxified hydrolysate was adopted as substrate for a batch-mode fermentation by the oleaginous yeast Lipomyces starkeyi. Lipid yield, content for single cell, production and maximum oil productivity were 20.2 wt%, 37 wt%, 3.7 g/L and 2.0 g/L/d respectively. This new generation oil, obtained from a negative value industrial waste, represents a promising platform chemical for the production of biodiesel, biosurfactants, animal feed and biobased plastics.


Assuntos
Lipomyces , Fermentação , Hidrólise , Açúcares , Leveduras
19.
Genes (Basel) ; 11(7)2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32650514

RESUMO

Centromeres function as a platform for the assembly of multiple kinetochore proteins and are essential for chromosome segregation. An active centromere is characterized by the presence of a centromere-specific histone H3 variant, CENP-A. Faithful centromeric localization of CENP-A is supported by heterochromatin in almost all eukaryotes; however, heterochromatin proteins have been lost in most Saccharomycotina. Here, identification of CENP-A (CENP-AL.s.) and heterochromatin protein 1 (Lsw1) in a Saccharomycotina species, the oleaginous yeast Lipomyces starkeyi, is reported. To determine if these proteins are functional, the proteins in S. pombe, a species widely used to study centromeres, were ectopically expressed. CENP-AL.s. localizes to centromeres and can be replaced with S. pombe CENP-A, indicating that CENP-AL.s. is a functional centromere-specific protein. Lsw1 binds at heterochromatin regions, and chromatin binding is dependent on methylation of histone H3 at lysine 9. In other species, self-interaction of heterochromatin protein 1 is thought to cause folding of chromatin, triggering transcription repression and heterochromatin formation. Consistent with this, it was found that Lsw1 can self-interact. L. starkeyi chromatin contains the methylation of histone H3 at lysine 9. These results indicated that L. starkeyi has a primitive heterochromatin structure and is an attractive model for analysis of centromere heterochromatin evolution.


Assuntos
Proteína Centromérica A/genética , Proteínas Cromossômicas não Histona/genética , Proteínas Fúngicas/genética , Lipomyces/genética , Proteína Centromérica A/metabolismo , Homólogo 5 da Proteína Cromobox , Proteínas Cromossômicas não Histona/metabolismo , Clonagem Molecular , Proteínas Fúngicas/metabolismo , Ligação Proteica , Domínios Proteicos , Schizosaccharomyces , Homologia de Sequência
20.
Curr Microbiol ; 77(10): 2821-2830, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32591923

RESUMO

The present study investigates the therapeutic properties of probiotic yeasts viz. Yarrowia lipolytica VIT-MN01, Kluyveromyces lactis VIT-MN02, Lipomyces starkeyi VIT-MN03, Saccharomycopsis fibuligera VIT-MN04 and Brettanomyces custersianus VIT-MN05. The antimutagenic activity of probiotic yeasts against the mutagens viz. Benzo[a]pyrene (B[a]P), and Sodium azide (SA) was tested. S. fibuligera VIT-MN04 showed highest antimutagenicity (75%). Binding ability on the mutagen acridine orange (AO) was tested and L. starkeyi VIT-MN03 was able to bind AO effectively (88%). The probiotic yeasts were treated with the genotoxins viz. 4-Nitroquinoline 1-Oxide (NQO) and Methylnitronitrosoguanidine (MNNG). The prominent changes in UV shift confirmed the reduction in genotoxic activity of S. fibuligera VIT-MN04 and L. starkeyi VIT-MN03, respectively. Significant viability of probiotic yeasts was noted after being exposed to mutagens and genotoxins. The adhesion capacity and anticancer activity were also assessed using Caco-2 and IEC-6 cell lines. Adhesion ability was found to be more in IEC-6 cells and remarkable antiproliferative activity was noted in Caco-2 cells compared to normal cells. Further, antagonistic activity of probiotic yeasts was investigated against S. typhimurium which was found to be more in S. fibuligera VIT-MN04 and L. starkeyi VIT-MN03. The inhibition of α-glucosidase and α-amylase activity confirmed the antidiabetic activity of probiotic yeasts. Antioxidant activity was also tested using standard assays. Therefore, based on the results, it can be concluded that probiotic yeasts can serve as potential therapeutic agents for the prevention and treatment of colon cancer, type 2 diabetes and gastrointestinal infections.


Assuntos
Probióticos , Leveduras , Brettanomyces/fisiologia , Células CACO-2 , Linhagem Celular , Neoplasias do Colo/microbiologia , Neoplasias do Colo/terapia , Diabetes Mellitus Tipo 2/microbiologia , Diabetes Mellitus Tipo 2/terapia , Humanos , Kluyveromyces/fisiologia , Lipomyces/fisiologia , Probióticos/uso terapêutico , Saccharomycopsis/fisiologia , Yarrowia/fisiologia , Leveduras/isolamento & purificação , Leveduras/fisiologia
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