ABSTRACT
Intense utilization and mining of fossil fuels for energy production have resulted in environmental pollution and climate change. Compared to fossil fuels, microalgae is considered as a promising candidate for biodiesel production due to its fast growth rate, high lipid content and no occupying arable land. However, monocultural microalgae bear high cost of harvesting, and are prone to contamination, making them incompetent compared with traditional renewable energy sources. Co-culture system induces self-flocculation, which may reduce the cost of microalgae harvesting and the possibility of contamination. In addition, the productivity of lipid and high-value by-products are higher in co-culture system. Therefore, co-culture system represents an economic, energy saving, and efficient technology. This review aims to highlight the advances in the co-culture system, including the mechanisms of interactions between microalgae and other microorganisms, the factors affecting the lipid production of co-culture, and the potential applications of co-culture system. Finally, the prospects and challenges to algal co-culture systems were also discussed.
Subject(s)
Biofuels , Biomass , Coculture Techniques , Flocculation , MicroalgaeABSTRACT
Lager yeast is the most popular yeast strain used for beer production in China. The flocculation of yeast plays an important role in cell separation at the end of fermentation. Therefore, appropriately enhancing the flocculation capability of the lager yeast without affecting its fermentation performance would be desirable for beer industry. Our previous study showed that the defect of gene RIM21 might contribute to the enhanced flocculation capability of a lager yeast G03. To further investigate the role of the RIM21 gene in flocculation of strain G03, this study constructed a RIM21-deleted mutant strain G03-RIM21Δ through homologous recombination. Deletion of RIM21 improved the flocculation capability of strain G03 during wort fermentation at 11 °C without changing its fermentation performance significantly. The expression of FLO5, Lg-FLO1 and some other genes involved in cell wall integrity pathway were up-regulated in strain G03-RIM21Δ. In addition, the disruption of RIM21 enhanced resistance of yeast cells to cell wall inhibitors. These results provide a basis for elucidating the flocculation mechanism of lager yeast under low-temperature fermentation conditions.
Subject(s)
Beer , Fermentation , Flocculation , Receptors, Cell Surface , Saccharomyces/metabolism , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/metabolismABSTRACT
Background: Fermentation strategies for bioethanol production that use flocculating Saccharomyces cerevisiae yeast need to account for the mechanism by which inhibitory compounds, generated in the hydrolysis of lignocellulosic materials, are tolerated and detoxified by a yeast floc. Results: Diffusion coefficients and first-order kinetic bioconversion rate coefficients were measured for three fermentation inhibitory compounds (furfural, hydroxymethylfurfural, and vanillin) in self-aggregated flocs of S. cerevisiae NRRL Y-265. Thièle-type moduli and internal effectiveness factors were obtained by simulating a simple steady-state spherical floc model. Conclusions: The obtained values for the Thiéle moduli and internal effectiveness factors showed that the bioconversion rate of the inhibitory compounds is the dominant phenomenon over mass transfer inside the flocs.
Subject(s)
Saccharomyces cerevisiae/metabolism , Biofuels , Yeasts , Benzaldehydes , Biodegradation, Environmental , Inactivation, Metabolic , Diffusion , Flocculation , Furaldehyde/analogs & derivativesABSTRACT
ABSTRACT A bacterium isolated from Sterkfontein dam was confirmed to produce bioflocculant with excellent flocculation activity. The 16S rDNA nucleotide sequence analyses revealed the bacteria to have 99% similarity to Streptomyces platensis strain HBUM174787 and the sequence was deposited in the Genbank as Streptomyces platensis with accession number FJ 486385.1. Culture conditions for optimal production of the bioflocculant included glucose as a sole carbon source, resulting in flocculating activity of 90%. Other optimal conditions included: peptone as nitrogen source; presence of Mg2+ as cations and inoculum size of 1.0% (v/v) at neutral pH of 7. Optimum dose of the purified bioflocculant for the clarification of 4 g/L kaolin clay suspension at neutral pH was 0.2 mg/mL. Energy Dispersive X-ray analysis confirmed elemental composition of the purified bioflocculant in mass proportion (%w/w): carbon (21.41), oxygen (35.59), sulphur (26.16), nitrogen (0.62) and potassium (7.48). Fourier Transform Infrared Spectroscopy (FTIR) indicated the presence of hydroxyl, carboxyl, methoxyl and amino group in the bioflocculant. The bioflocculant produced by S. platensis removed chemical oxygen demand (COD) in river water and meat processing wastewater at efficiencies of 63.1 and 46.6% respectively and reduced their turbidity by 84.3 and 75.6% respectively. The high flocculating rate and removal efficiencies displayed by S. platensis suggests its industrial application in wastewater treatment.
Subject(s)
Streptomyces/chemistry , Bacterial Proteins/metabolism , Wastewater/chemistry , Streptomyces/isolation & purification , Streptomyces/genetics , Streptomyces/metabolism , Bacterial Proteins/genetics , Water Microbiology , Carbon/metabolism , Water Purification , Rivers/chemistry , Flocculation , Nitrogen/metabolismABSTRACT
The cation-dependent galactose-specific flocculation activity of the Schizosaccharomyces pombe null mutant of lkh1⁺, the gene encoding LAMMER kinase homolog, has previously been reported by our group. Here, we show that disruption of prk1⁺, another flocculation associated regulatory kinase encoding gene, also resulted in cation-dependent galactose-specific flocculation. Deletion of prk1 increased the flocculation phenotype of the lkh1⁺ null mutant and its overexpression reversed the flocculation of cells caused by lkh1 deletion. Transcript levels of prk1⁺ were also decreased by lkh1⁺ deletion. Cumulatively, these results indicate that Lkh1 is one of the negative regulators acting upstream of Prk1, regulating non-sexual flocculation in fission yeast.
Subject(s)
Flocculation , Phenotype , Phosphotransferases , SchizosaccharomycesABSTRACT
Abstract This study aimed to evaluate the elution-concentration methodology based on skimmed milk flocculation from three varieties of tomatoes (Solanum lycopersicum L. [globe], Solanum lycopersicum var. cerasiforme [cherry] and hybrid cocktail [grape tomato]) for further monitoring of field samples. Spiking experiments were performed to determine the success rate and efficiency recovery of human norovirus (NoV) genogroup II, norovirus murine-1 (MNV-1) used as sample process control virus and human adenovirus (HAdV). Mean values of 18.8%, 2.8% and 44.0% were observed for NoV GII, MNV-1 and HAdV, respectively with differences according to the types of tomatoes, with lower efficiency for cherry tomatoes. Analysis of 90 samples, obtained at commercial establishments in the metropolitan region of Rio de Janeiro State, revealed 4.5% positivity for HAdV. Bacterial analysis was also performed with no detection of Salmonella spp., L. monocytogenes and fecal coliforms. Data demonstrated that the skimmed milk flocculation method is suitable for recovering HAdV from tomatoes and highlights the need for considering investigation in order to improve food safety.
Subject(s)
Animals , Cattle , Viruses/isolation & purification , Solanum lycopersicum/chemistry , Milk/chemistry , Food Microbiology/methods , Fruit/virology , Viruses/classification , Viruses/genetics , Solanum lycopersicum/classification , Solanum lycopersicum/virology , Flocculation , Food Microbiology/instrumentation , Fruit/classification , Fruit/chemistryABSTRACT
Microalgae have been identified as promising candidates for biorefinery of value-added molecules. The valuable products from microalgae include polyunsaturated fatty acids and pigments, clean and sustainable energy (e.g. biodiesel). Nevertheless, high cost for microalgae biomass harvesting has restricted the industrial application of microalgae. Flocculation, compared with other microalgae harvesting methods, has distinguished itself as a promising method with low cost and easy operation. Here, we reviewed the methods of microalgae harvesting using flocculation, including chemical flocculation, physical flocculation and biological flocculation, and the progress and prospect in bio-flocculation are especially focused. Harvesting microalgae via bio-flocculation, especially using bio-flocculant and microalgal strains that is self-flocculated, is one of the eco-friendly, cost-effective and efficient microalgae harvesting methods.
Subject(s)
Biofuels , Biomass , Flocculation , MicroalgaeABSTRACT
Flocculent gene FLO1 and its truncated form FLO1c with complete deletion of repeat unit C were expressed in a non-flocculent industrial strain Saccharomyces cerevisiae CE6 to generate recombinant flocculent strains 6-AF1 and 6-AF1c respectively. Both strains of 6-AF1 and 6-AF1c displayed strong flocculation and better cell growth than the control strain CE6-V carrying the empty vector under acetic acid stress. Moreover, the flocculent strains converted glucose to ethanol at much higher rates than the control strain CE6-V under acetic acid stress. In the presence of 0.6% (V/V) acetic acid, the average ethanol production rates of 6-AF1 and 6-AF1c were 1.56 and 1.62 times of that of strain CE6-V, while the ethanol production rates of 6-AF1 and 6-AF1c were 1.21 and 1.78 times of that of strain CE6-V under 1.0% acetic acid stress. Results in this study indicate that acetic acid tolerance and fermentation performance of industrial S. cerevisiae under acetic acid stress can be improved largely by flocculation endowed by expression of flocculent genes, especially FLO1c.
Subject(s)
Acetic Acid , Chemistry , Ethanol , Fermentation , Flocculation , Glucose , Industrial Microbiology , Mannose-Binding Lectins , Genetics , Saccharomyces cerevisiae , Genetics , Metabolism , Saccharomyces cerevisiae Proteins , GeneticsABSTRACT
Doze vacas lactantes Holandês-Gir (1/2), em sistema de pasto rotativo de Panicum maximum cv. Mombaça, foram suplementadas com concentrados contendo milho seco finamente moído (MM), milho expandido (ME), milho floculado a vapor (MF) ou milho moído reidratado e ensilado (MU). O delineamento experimental adotado foi o de quadrado latino 4 x 4, com três repetições. O consumo de pasto foi maior quando as vacas foram suplementadas com MF, o que se refletiu em maior consumo de MS, PB, FDN para o mesmo tratamento. A digestibilidade aparente da MS foi maior para as dietas de MF e MM. A digestibilidade aparente da FDN foi menor para MU. A produção e composição do leite das vacas não diferiram entre os tratamentos, entretanto a eficiência alimentar foi menor para MF...
Twelve lactating Holstein-Gyr (1/2) cows in a rotational grazing system with Panicum maximum cv. Mombasa were supplemented with different concentrates containing finely ground dried corn (MM), expanded corn (ME), steam flaked corn (MF) or silage of re-hydrated ground corn (MU). The experiment was arranged in a 4 x 4 Latin square design with three replications. Pasture intake was higher when cows were supplemented with MF, which resulted in higher DM, CP, and NDF. The apparent digestibility of DM was higher for MF and MM diets. The NDF apparent digestibility was lower for MU. Milk yield and composition did not differ between treatments; however, feed efficiency was lower for MF...
Subject(s)
Animals , Cattle , Brachiaria/adverse effects , Diet/veterinary , Flocculation , Panicum/adverse effects , Breast-Milk Substitutes , Poaceae , Infant Nutritional Physiological PhenomenaABSTRACT
Arthrosphira (Spirulina) platensis apresenta substâncias de interesse nas indústrias alimentícia, farmacêutica e cosmética. A produção industrial envolve uma quantidade muito grande de água e sua viabilidade deve contemplar o reuso do meio, visando uma diminuição de custos com nutrientes, bem como da poluição ambiental, tornando-se assim um processo sustentável. O presente trabalho teve como objetivo principal a avaliação do reaproveitamento do meio no cultivo de A. platensis usando tratamentos físico-químicos de floculação e adsorção. Para tanto, tal cianobactéria foi cultivada em fotobiorreator (FBR) tubular em processos de batelada alimentada e contínuo em intensidade luminosa de 120 µmol fótons m-2 s-1, sob controle de pH. Foram desenvolvidas técnicas de tratamento de meio de cultivo proveniente de processo descontínuo alimentado de A. platensis para a remoção de matéria orgânica (MO) e pigmentos (60 - 96 %), permitindo assim seu reuso em novos cultivos. A. platensis foi cultivada nos meios tratados utilizando frascos Erlenmeyer, com avaliação de parâmetros como concentração celular máxima (Xm), conteúdo de clorofila-a (Chl) e conteúdo de proteína na biomassa seca (PTN). No processo simultâneo de floculação e adsorção com carvão ativado em pó (CAP), foram testados dois agentes floculantes, cloreto férrico (F) e sulfato férrico (S) bem como diferentes tempos de contato. No processo simultâneo de floculação com F e adsorção com CAP, as condições ótimas foram: CAP = 24,4 mg L-1 e F = 20,3 mg L-1durante 30,4 min de tempo de contato; com obtenção de: Xm = 4893 ± 33 mg L-1, Chl = 24,3 ± 0,1 mg g-1, PTN = 36,1 ± 0,6 %. As condições ótimas de tratamento simultâneo de floculação com S e adsorção com CAP foram: CAP = 40,0 mg L-1 e S = 32,8 mg L-1 durante 36,1 min de tempo de contato, com obtenção de: Xm = 4863 ± 64 mg L-1, Chl = 24,5 ± 0,6 mg g-1, PTN = 60,1 ± 0,6 %. No processo sequencial de floculação com F seguido de adsorção com carvão ativado granulado (CAG), as condições ótimas foram atingidas com: CAG = 108,4 g e F = 10,0 mg L-1 durante 30,8 min de tempo de residência; obtendo-se: Xm = 3140 ± 77 mg L-1, Chl = 35,4 ± 0,2 mg g-1, PTN = 44,9 ± 0,0 %. Adicionalmente, os meios tratados nessas condições ótimas de cada tratamento, também foram testados em FBR tubulares, atingindo valores de Xm, Chl e PTN maiores do que os obtidos com meio padrão. Além disso, o processo simultâneo de cultivo celular em FBR tubulares e adsorção contínua do meio de cultivo exaurido em coluna de CAG removeu 51 - 79 % de MO e pigmentos. Foi demonstrado que uma proporção de 75 % de meio tratado no meio de alimentação não produz diminuição significativa de produtividade celular (PX) e os resultados foram: concentração celular em estado estacionário (Xs) de 1568 ± 15 mg L-1, PX = 941 mg L-1 d-1, PTN = 42,0 ± 0,6 %, com diminuição de 65 % no custo de meio de cultivo. Por fim, conclui-se que é viável a utilização de processos físico-químicos no tratamento de meio a ser reaproveitado no cultivo de A. platensis, inclusive em FBR tubulares, com apreciável incremento de clorofila-a e proteínas na biomassa obtida em meio tratado
Arthrospira (Spirulina) platensis have compounds of interest in the food, pharmaceutical and cosmetic industries. Industrial production involves high volumes of water and its viability should contemplate medium reuse, aiming to reduce not only nutrient costs, but also environmental pollution, thus becoming a sustainable process. This work had as main objective the evaluation of A. platensis culture medium reuse through the physicochemical treatments flocculation and adsorption. Thus, this cyanobacterium was cultivated in tubular photobioreactor (PBR) by fed-batch and continuous processes at light intensity 120 µmol photons m-2 s-1 under pH control. Treatment techniques were developed for culture medium from fed-batch process to properly removal of organic matter (OM) and pigments (60 - 96 %), thus allowing its reuse in new cultures. A. platensis was cultivated in treated medium using Erlenmeyer flasks, with the evaluation of parameters such as maximum cell concentration (Xm), chlorophyll content (Chl) and protein content in dry biomass (PTN). For simultaneous flocculation and adsorption with powdered activated carbon (PAC), two flocculants were used: ferric chloride (F) and ferric sulfate (S), as well as different contact times. In the simultaneous process of F flocculation and PAC adsorption, optimum conditions were: PAC = 24.4 mg L-1 and F = 20.3 mg L-1 for 30.4 min contact time; results were: Xm = 4893 ± 33 mg L-1, Chl = 24.3 ± 0.1 mg g-1, PTN = 36.1 ± 0.6 %. Optimal conditions in the simultaneous process of S flocculation and PAC adsorption were: PAC = 40.0 mg L-1 and S = 32.8 mg L-1 for 36.1 min contact time; results were: Xm = 4863 ± 64 mg L-1, Chl = 24.5 ± 0.6 mg g-1, PTN = 60.1 ± 0.6 %. In the sequential process of F flocculation followed by adsorption with granular activated carbon (GAC), optimal conditions were reached at GAC = 108.4 g and F = 10.0 mg L-1 for 30.8 min of residence time, at which Xm = 3140 ± 77 mg L-1, Chl = 35.4 ± 0.2 mg g-1 and PTNPTN = 44.9 ± 0.0 % were obtained. Moreover, medium treated at each optimal condition were also tested in tubular PBRs, reaching values of Xm, Chl and PTN higher than those obtained with standard medium. Furthermore, the simultaneous process of cell cultivation in tubular PBR and continuous adsorption of spent cultivation medium through GAC column removed 51 - 79 % of OM and pigments. It was showed that 75 % of treated medium in the feed medium does not cause significant decrease in cell productivity (PX) and results were: steady-state cell concentration (Xs) = 1568 ± 15 mg L-1, PX = 941 mg L-1 d-1, PTN = 42.0 ± 0.6 %, with 65 % reduction in medium price. At last, it can be inferred that the use of physicochemical processes in medium treatment is feasible for reuse in A. platensis cultivation, including that in tubular PBR, leading to considerable increase in chlorophyll and protein contents of the biomass obtained with treated medium
Subject(s)
Biomass , Culture Media/analysis , Spirulina/growth & development , Flocculation , Adsorption , Bioreactors , MicrobiologyABSTRACT
Propionic acid, a major inhibitor to yeast cells, was accumulated during continuous ethanol fermentation from corn meal hydrolysate by the flocculating yeast under stillage backset conditions. Based on its inhibition mechanism in yeast cells, strategies were developed for alleviating this effect. Firstly, high temperature processes such as medium sterilization generated more propionic acid, which should be avoided. Propionic acid was reduced significantly during ethanol fermentation without medium sterilization, and concentrations of biomass and ethanol increased by 59.3% and 7.4%, respectively. Secondly, the running time of stillage backset should be controlled so that propionic acid accumulated would be lower than its half inhibition concentration IC50 (40 mmol/L). Finally, because low pH augmented propionic acid inhibition in yeast cells, a higher pH of 5.5 was validated to be suitable for ethanol fermentation under the stillage backset condition.
Subject(s)
Biomass , Ethanol , Metabolism , Fermentation , Flocculation , Propionates , Chemistry , Yeasts , MetabolismABSTRACT
To optimize the pretreatment of Huanglian Jiedu decoction before ceramic membranes and verify the effect of different pretreatments in multiple model system existed in Chinese herb aqueous extract. The solution environment of Huanglian Jiedu decoction was adjusted by different pretreatments. The flux of microfiltration, transmittance of the ingredients and removal rate of common polymers were as indicators to study the effect of different solution environment It was found that flocculation had higher stable permeate flux, followed by vacuuming filtration and adjusting pH to 9. The removal rate of common polymers was comparatively high. The removal rate of protein was slightly lower than the simulated solution. The transmittance of index components were higher when adjust pH and flocculation. Membrane blocking resistance was the major factor in membrane fouling. Based on the above indicators, the effect of flocculation was comparatively significant, followed by adjusting pH to 9.
Subject(s)
Ceramics , Chemistry , Drugs, Chinese Herbal , Chemistry , Flocculation , Membranes, Artificial , Polymers , Chemistry , Solutions , Chemistry , Ultrafiltration , MethodsABSTRACT
Lead is one of the four heavy metals that has a profound damaging effects on human health. In the recent past there has been an increasing global concern for development of sustainable bioremediation technologies for detoxification of lead contaminant. Present investigation highlights for lead biosorption by a newly isolated novel bacterial species; Achromobacter sp. TL-3 strain, isolated from activated sludge samples contaminated with heavy metals (collected from oil refinery, Assam, North-East India). For isolation of lead tolerant bacteria, sludge samples were enriched into Luria Broth medium supplemented separately with a range of lead nitrate; 250, 500, 750, 1000, 1250 and 1500 ppm respectively. The bacterial consortium that could tolerate 1500 ppm of lead nitrate was selected further for purification of lead tolerant bacterial isolates. Purified lead tolerant bacterial isolates were then eventually inoculated into production medium supplemented with ethanol and glycerol as carbon and energy source to investigate for bioflocculant production. Bioflocculant production was estimated by monitoring the potential of lead tolerant bacterial isolate to flocculate Kaolin clay in presence of 1% CaCl2. Compared to other isolates, TL-3 isolate demonstrated for maximum bioflocculant activity of 95% and thus was identified based on 16S rRNA gene sequence analysis. TL3 isolate revealed maximum homology (98%) with Achromobacter sp. and thus designated as Achromobacter sp. TL-3. Bioflocculant activity of TL-3 isolate was correlated with the change in pH and growth. Achromobacter sp. TL-3 has significant potential for lead biosorption and can be effectively employed for detoxification of lead contaminated waste effluents/waste waters.
Subject(s)
Achromobacter/classification , Achromobacter/drug effects , Achromobacter/isolation & purification , Adaptation, Physiological , Base Sequence , Culture Media , DNA Primers , Flocculation , Lead/toxicity , Molecular Sequence Data , Phylogeny , Sewage , Spectrophotometry, AtomicABSTRACT
Makgeolli is a traditional cloudy-white Korean rice wine with an alcohol content of 6~7%. The present study investigated the morphological characteristics, carbon-utilizing ability, fatty acid composition, alcohol resistance, glucose tolerance, and flocculence of Saccharomyces cerevisiae Y98-5 and Pichia anomala Y197-13, non-S. cerevisiae isolated from Nuruk, which is used in brewing Makgeolli. Similar morphological characteristics were observed for both isolated wild yeast strains; and the carbon source assimilation of Y197-13 differed from that of other P. anomala strains. Strain Y197-13 was negative for D-trehalose, mannitol, arbutin, I-erythritol, and succinic acid. The major cellular fatty acids of strain Y197-13 included C18:2n6c (33.94%), C18:1n9c (26.97%) and C16:0 (20.57%). Strain Y197-13 was Crabtree-negative, with 60% cell viability at 12% (v/v) ethanol. The flocculation level of strain Y197-13 was 8.38%, resulting in its classification as a non-flocculent yeast.
Subject(s)
Arbutin , Carbon , Cell Survival , Ethanol , Fatty Acids , Flocculation , Glucose , Mannitol , Pichia , Saccharomyces cerevisiae , Sprains and Strains , Succinic Acid , Wine , YeastsABSTRACT
The aim of this work was to optimize the coagulation-flocculation [CF] process applied to municipal wastewaters [WW]. Optimization of CF was performed to minimize chemical oxygen demand [COD], turbidity, sludge produced, and some metals in sludge. A Box-Behnken design was used to evaluate the effects and interactions of three factors such as type of biopolymer [guar, mesquite seed gum and Opuntia mucilage], dose of biopolymer [25, 50 and 75 mg/L] and initial organic load of wastewaters WW [725, 1,425 and 1,325 mg COD/L]. Regarding the statistical analysis, Results were assessed with various descriptive statistics such as p value, lack of fit [F-test], coefficient of R2 determination and adequate precision [AP] values. p values 0.05 show that the F-statistics was insignificant implying significant model correlation between the variables and process responses. Regarding the fit of the model, the obtained R2 values were up to 0.98 for sludge produced, 0.94 for COD removal, 0.91 for Cd, 0.90 for turbidity removal, and 0.75 for sludge density. It is noteworthy that response surface methodology [RSM] also allowed optimizing de CF process. Employing this methodology it is feasible to determine COD, turbidity, and salts removals, as well as the amount and quality of the produced sludges under hypothetical conditions within predetermined parameter ranges, without the need of carrying out experimental runs
Subject(s)
Biopolymers , Flocculation , Sewage , Biological Oxygen Demand AnalysisABSTRACT
In this work attempts were made to evaluate K[+]-SDS and hydrocolloid polymer-SDS interactions in flocculation of megestrol acetate dispersions to enhancetheir stability as a part of suspension formulation. Different dispersions of micronized megestrol acetate and SDS were prepared. KCl and KH[2]PO[4] and their corresponding sodium salts were added to the dispersions and the preparations were evaluated using general physicochemical and stability tests including appearance, sedimentation volume, sedimentation rate and redispersibility. Addition of polyols and hydrocolloid polymers to the SDS containing dispersions was also investigated for possible instabilities.SDS deflocculated the initial megestrol acetate dispersions. The use of potassium salts unlike the sodium salts flocculated the dispersion particles due to precipitation reaction of potassium ions and the adsorbed SDS. Additionally the uncharged hydrocolloid polymers MC and HPMC in contrast to the ionic polymers xanthan gum and NaCMC showed incompatibility due to their interaction with SDS. K[+]- SDS interactions have proved useful in protein and DNA analysis studies and we found this precipitation reaction to be applicable in flocculation of pharmaceutical suspensions containing SDS
Subject(s)
Potassium/chemistry , Suspensions , Colloids , Megestrol Acetate , FlocculationABSTRACT
Yeast flocculation is described as a reversible, asexual and calcium dependent process, in which cells adhere to form flocs by interaction of specific cell surface proteins named flocculins on yeast cells with mannose residues present on the cell wall of adjacent yeast cells. Yeast flocculation provides a very economical and convenient pathway for separation of yeast cells from the fermentation broth or removal of heavy metal ions from effluent. A large number of tandem repeats have been found in genes encoding flocculins, which not only have great regulatory effect on the structure and function of flocculins, generating the diversity of flocculation characteristics, but lead to genetic instability in flocculation as well for driving slippage and recombination reactions within and between FLO genes. Here, the research progress in effect of variation of tandem repeats in FLO genes on flocculation characteristics and genetic stability were reviewed to direct and promote the controllable application of flocculation in industrial fermentation process and environmental remediation.
Subject(s)
Fermentation , Flocculation , Mannose , Membrane Proteins , Genetics , Saccharomyces cerevisiae , Genetics , Saccharomyces cerevisiae Proteins , Genetics , Tandem Repeat SequencesABSTRACT
Background: Robust second generation bioethanol processes require microorganisms able to ferment inhibitory lignocellullosic hydrolysates. In this study, the inhibitor tolerance and flocculation characteristics of Saccharomyces cerevisiae CCUG53310 were evaluated in comparison with S. cerevisiae CBS8066. Results: The flocculating strain CCUG53310 could rapidly ferment all hexoses in dilute acid spruce hydrolysate, while CBS8066 was strongly inhibited in this medium. In synthetic inhibitory media, CCUG53310 was more tolerant to carboxylic acids and furan aldehydes, but more sensitive than CBS8066 to phenolic compounds. Despite the higher tolerance, the increase in expression of the YAP1, ATR1 and FLR1 genes, known to confer resistance to lignocellulose-derived inhibitors, was generally smaller in CCUG53310 than in CBS8066 in inhibitory media. The flocculation of CCUG53310 was linked to the expression of FLO8, FLO10 and one or more of FLO1, FLO5 or FLO9. Flocculation depended on cell wall proteins and Ca2+ ions, but was almost unaffected by other compounds and pH values typical for lignocellulosic media. Conclusions: S. cerevisiae CCUG53310 can be characterised as being very robust, with great potential for industrial fermentation of lignocellulosic hydrolysates relatively low in phenolic inhibitors.
Subject(s)
Biofuels , Ethanol , Lignin , Saccharomyces cerevisiae , Yeasts , Cellulose , Fermentation , FlocculationABSTRACT
One of the industries dependent on oil compounds that play an important role in economy, preserve resources and oil reserves, as well as environmental protection is the secondary refinery Oil industries. The efficiency of Coagulation, flocculation and advanced oxidation process in the Effluent treatment industry was studied. This study is a descriptive- quasi-experimental that effluent pollution quality measured with COD. Physicochemical processes of coagulation, flocculation, by using conventional coagulants and oxidation with ozone for the removal to access environmental discharge effluent standards were studied. Coagulants such as aluminum sulfate, ferric chloride, sodium silicate, poly aluminum chloride were evaluated. Jartest was used to determine the efficiency of coagulation and flocculation. Samples were collected from Salafchegan industrial district in Qom. Examination methods were extracted from Standard methods for water and wastewater examination. Initial experiments showed that BOD, indicating biological treatment wastewater, in comparison with COD, indicating chemical oxygen demand of wastewater is very low. Thus, the application of biological processes of effluent treatment without using chemical processes, not performance and not economic. The experiment showed that the amount of COD in raw effluent was varied from 38000 to 78000mg/l. Using advanced oxidation with O[3] in pH=11.5 can reach 77.5% and in pH=9 in 57.2 and in pH=3.25 in 21.3 COD removal efficiency respectively. According to the results, advanced oxidation process prior to biological effluent treatment of the second refinery oil industries is effective in eliminating pollutants and toxic substances
Subject(s)
Industry , Flocculation , Oxidation-Reduction , Alum Compounds , Ferric Compounds , Chlorides , Silicates , Aluminum HydroxideABSTRACT
<p><b>OBJECTIVE</b>To study the effect of quaternary ammonium salt of chitosan (HACC) in purifying aqueous extracts of Zhisou Dingchuan oral solution.</p><p><b>METHOD</b>Modified quaternary ammonium salt of chitosan was used to flocculate aqueous extracts of Zhisou dingchuan oral solution, with turbidity degree and the retention rate of ephedrine and glycyrrhizin as indicators, to detect the influences of flocculant dosage, suspension temperature, mixing speed and time on flocculation effect. The optimum process conditions were found through orthogonal experimental design.</p><p><b>RESULT</b>The optimum process conditions: the flocculation temperature 30 degrees C, HACC's dosage 0.4 g x L(-1), the fast mixing speed 500 r x min(-1) and its time 1 min, the slow mixing speed 50 r x min(-1) and it time 2.4 10 min. Under the conditions, the retention rate of ephedrine was 97.6%, the turbidity degree was 1.1 NTU and 2.8 NTU after 30 days.</p><p><b>CONCLUSION</b>HACC can be used to purify aqueous extracts of Zhisou Dingchuan oral solution.</p>