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1.
Binding capacity of Mg2+ ions, the biomass yield and the cell wall structure of Candida utilis ATCC 9950 cultivated in the media containing magnesium and mannose were evaluated in the study. Mannose has been added to two types of culture media: not enriched and enriched with Mg2+ ions. The YPD medium was used as a control while the experimental media (without or with Mg2+ ions) have been prepared by replacing glucose in the YPD medium by 1% (YPDM) or 2% (YPM) of mannose. The highest content of magnesium (5.39 and 5.42 mg/gd.w.) as well as the highest biomass yield (15.22 and 14.03 gd.w./L) were observed after 24 h of cultivation in the media enriched with magnesium and supplemented with mannose. The yeast cultivated for 48 h in those media were also characterized by thicker cell walls (74.3 and 67.7 nm). Introduction of mannose to the cultivation media was the factor that has influenced biosorption of magnesium ions as the result of twofold thickening of the mannoprotein layer of the cell wall of Candida utilis ATCC 9950 yeast.  相似文献   

2.
A strain of Syncephalastrum racemosum isolated from herbivores feces was studied for chitosan production using sugar cane substrates, such as juice or molasses, from Northeast Brazil. S. racemosus was batch grown in shake flasks over 5 days using sugar cane juice or molasses as carbon source. The effect of supplementary nitrogen source was studied by supplying medium with yeast extract or ammonium sulphate. The highest yield of the biopolymer (30 mg chitosan. g?1 sucrose) was obtained using sugar cane juice (21 g sucrose. L?1) plus 0.3% yeast extract. Batch fermentation in a 5-L bioreactor using the same medium, increased the yield to 50 mg chitosan. g?1 sucrose. Chitosan extracted from S. racemosus cultured in sugar cane juice medium showed a low degree of acetylation with a high D-glucosamine content.  相似文献   

3.
BACKGROUND: The paper discusses biosorption of microelements by a freshwater macroalga Pithophora varia Wille to produce biological feed supplement for livestock. The biomass was enriched with microelements recommended by feeding standards in a single and a multi‐metal system. RESULTS: The equilibrium of biosorption was described by using a Langmuir model and the following values of the maximum biosorption capacity in the single‐metal system were obtained: Zn(II), 61.1 mg g?1; Co(II), 52.3 mg g?1; Cu(II), 55.7 mg g?1; and Mn(II), 38.3 mg g?1. The average value of maximum biosorption capacity expressed in molar units for all the cations was equal 1.7 ± 0.2 meq g?1, suggesting chemical rather than physical biosorption. It was also found that the mechanism of biosorption was due to cation exchange of alkali and alkaline earth metals with microelements. The biomass was also enriched with microelements in multi‐metal system. The total metal ion binding capacity in the multi‐metal system was two‐fold lower than in the single‐metal system and was 0.90 meq g?1 in the preparation for laying hens and 0.95 meq g?1 in the supplement for swine. CONCLUSION: Finally, the level of supplementation of livestock feed (with enriched single‐ and multi‐metal system macroalga), to cover 25% of total requirements for microelements, according to feeding standards, was provided. Copyright © 2008 Society of Chemical Industry  相似文献   

4.
This study aimed to optimise aqueous extraction conditions for total phenolic compounds (TPC) from Davidson's plum (Davidsonia pruriens F. Muell) and to assess the physicochemical and antioxidant properties of the phenolic‐enriched extract. The results showed that temperature, time and ratio significantly affected the extraction of TPC. Optimization of extraction conditions was performed using response surface methodology (RSM) utilising a Box–Behnken design. Optimal extraction conditions were determined to be temperature: 90 °C, extraction time: 30 min and solvent to mass ratio: 20:1 mL g?1. The extracted solid obtained under these conditions had low‐moisture content, high water solubility and contained 45 mg GAE g?1 of TPC, 22 mg RUE g?1 of flavonoids, 3.2 mg CAE g?1 of proanthocyanidins, 2 mg CGE g?1 of anthocyanidins and 56 mg ACE g?1 vitamin C. The extract possessed potent antioxidant capacity, but was comparatively lower than those of vitamin E and BHT. Thus, Davidson's plum should be further investigated for its potential health promoting benefits and utilisation in the nutraceutical and food industries.  相似文献   

5.
BACKGROUND: The purpose of this study was to evaluate the effects of leaf order or crop season on anthocyanins and other chemicals in the anthocyanin‐rich tea cultivar ‘Sunrouge’ (Camellia sinensis x C. taliensis) by using high‐performance liquid chromatography, and to study the effect of ‘Sunrouge’ extract on acetylcholinesterase (AChE) activity in human neuroblastoma SK‐N‐SH cells. RESULTS: The total anthocyanin content was higher in the third (3.09 mg g?1) than in the second (2.24 mg g?1) or first crop season (1.79 mg g?1). The amount of anthocyanins contained in the stem was high (1.61 mg g?1). In the third crop season, the concentrations of delphinidin‐3‐O‐β‐D ‐(6‐(E)‐p‐coumaroyl)galactopyranoside (DCGa), cyanidin‐3‐O‐β‐D ‐(6‐(E)‐p‐coumaroyl)galactopyranoside, delphinidin‐3‐O‐β‐D ‐galactopyranoside, delphinidin‐3‐O‐β‐D ‐(6‐O‐(Z)‐p‐coumaroyl)galactopyranoside, cyanidin‐3‐O‐β‐D ‐galactoside, and delphinidin‐3‐O‐β‐D ‐glucoside were 1.57 mg g?1, 0.52 mg g?1, 0.40 mg g?1, 0.22 mg g?1, 0.14 mg g?1, and 0.11 mg g?1, respectively. DCGa accounted for about 50% of the anthocyanins present. The suppressive effect of ‘Sunrouge’ water extract on AChE activity in human neuroblastoma SK‐N‐SH cells was the strongest among the three tea cultivars (‘Sunrouge’, ‘Yabukita’ and ‘Benifuuki’). CONCLUSION: These results suggested that ‘Sunrouge’ might protect humans from humans from AChE‐related diseases by suppressing AChE activity. To obtain sufficient amounts of anthocyanins, catechins and/or caffeine for a functional food material, ‘Sunrouge’ from the third crop season should be used. Copyright © 2012 Society of Chemical Industry  相似文献   

6.
Esters and higher alcohols produced by yeast during the fermentation of wort have the greatest impact on the smell and taste of beer. Alcohol acetyltransferase, which is mainly encoded by the ATF1 gene, is one of the most important enzymes for acetate ester synthesis. Cytosolic branched-chain amino acid aminotransferase, on the other hand, which is encoded by the BAT2 gene, plays an important role in the production of branched-chain alcohols. The objective of this study is to construct engineered brewer’s yeast strains that produce more acetate esters and less higher alcohols. Industrial brewer’s yeast strain S5 was used as the parental strain to construct ATF1 overexpression and BAT2 deletion mutants. The engineered strains S5-2 and S5-4, which feature partial BAT2 allelic genes replaced by the constructed ATF1 overexpression cassette, were obtained. The ester production of the engineered strains was observed to increase significantly compared with that of the parental cells. The concentrations of ethyl acetate produced by the engineered strains S5-2 and S5-4 increased to 78.88 and 117.40 mg L?1, respectively, or about 7.7-fold and 11.5-fold higher than that produced by parental S5 cells. The isoamyl acetate produced by S5-2 and S5-4 also increased to 5.14 and 9.25 mg L?1, respectively; by contrast, no isoamyl acetate was detected in the fermentation sample of the parental strain S5. Moreover, S5-2 and S5-4, respectively, produced about 65 and 51 % of higher alcohols produced by the parental strain. The increase in acetate ester content and decrease in higher alcohol concentration shown by the engineered brewer’s yeast strains at the end of fermentation process indicate that the new strains are useful in future developments in the wheat beer industry.  相似文献   

7.
The gene (POFI) which imparts to certain yeasts the ability to decarboxylate phenolic acids to corresponding phenolic compounds has been analysed by restriction mapping. New restriction sites have been used to examine differences between Pof+ and Pof? Saccharomyces cerevisiae strains. Southern Blot analysis of selected yeast strains has demonstrated that the POFI gene sequence is highly conserved between the Pof+ strain from which the gene was cloned, two Pof? lager brewing strains and one Pof+ Saccharomyces brewery isolate. However, sequence differences have been found between the original Pof+ strain, a Pof?laboratory strain and a Pof? ale brewing strain.  相似文献   

8.
The efficacy of three strains of Saccharomyces cerevisiae in the production of vodka from potato hydrolysate was evaluated. For each isolate, two treatments were performed: one containing potato hydrolysate (11% w/w of soluble solids) and the other containing potato hydrolysate supplemented with sucrose (17% w/w) in the fermentation medium. The best results were obtained using a baker's yeast in the second treatment, which showed higher substrate‐to‐product conversion (0.47 g ethanol g?1 total reducing sugars), higher fermentation yield (91.4%) and a higher ethanol content (6.05% v/v). Following fermentation, the medium was clarified using centrifugation, and two successive distillations and filtrations were conducted. The results were examined by referring to the standards for vodka, as established by Brazilian legislation. The ethanol concentration (39.7% v/v) fell within the legally stipulated range, and the levels of copper and furfural remained undetectable. However, the methanol (35.04 mg 100 mL?1 of anhydrous alcohol) content and the levels of some secondary compounds (148.33 mg 100 mL?1) were both higher than the guidelines (20 and ≤50 mg 100 mL?1, respectively). Copyright © 2016 The Institute of Brewing & Distilling  相似文献   

9.
The influences of dietary supplementation with α‐tocopheryl acetate (α‐TA) and of processing (by hard‐boiling and scrambling) of eggs enriched with ω3 fatty acids, either very long‐chain ω3 polyunsaturated fatty acids (VLC ω3 PUFAs) or linolenic acid (LNA), on fatty acid composition, α‐tocopherol content and lipid oxidation (thiobarbituric acid (TBA) values) were studied. Four dietary treatments were formulated from a basal diet containing 40 g kg?1 linseed oil (LO) or fish oil (FO) combined with either 0 or 100 mg α‐TA kg?1 of feed. Eggs from LO treatments were enriched with LNA and those from FO treatments were rich in VLC ω3 PUFAs. Neither processing nor dietary supplementation with α‐TA modified greatly the fatty acid profile of eggs. Dietary supplementation with α‐TA increased the α‐tocopherol content of eggs (187.2 versus 407.9 µg g?1 dry matter). Eggs from FO treatments showed lower α‐tocopherol content than those from LO treatments (273.5 versus 321.6 µg g?1 dry matter), and processing of eggs enriched with VLC ω3 PUFA reduced the α‐tocopherol content by a significant 16%. Moreover, processing of eggs increased lipid oxidation two‐ to nine‐fold. Oxidation levels of hard‐boiled eggs were 30.4% higher than those of scrambled eggs. TBA values in hard‐boiled and scrambled eggs were significantly reduced when 100 mg α‐TA kg?1 of feed supplemented the diet only in those eggs enriched with VLC ω3 PUFA (from FO treatments). Copyright © 2003 Society of Chemical Industry  相似文献   

10.
本文利用PEG诱导原生质细胞融合技术,进行糖化酵母单倍体H-3(2)-2菌株与优良嗜杀啤酒酵母5-24菌株的原生质体细胞融合实验。在对融合亲本不做任何遗传标记的情况下,将糖化酵母的糖化酶基因(STA)转移到嗜杀啤酒酵母中,获得1株高发酵度嗜杀啤酒酵母F-35-88菌株。对融合子F-35-88菌株分析表明,融合子遗传性状稳定,不仅具有较强的糊精利用能力和较高的发酵度,而且具有嗜杀活性,对于干啤酒的生产及提高成品酒的生物稳定性有明显效果。  相似文献   

11.
Effect of pretreatments with 1 w/v% sodium hydrogen sulphite (NaHSO3) and 1 w/v% calcium chloride (CaCl2) and drying temperatures (55, 60 and 65 °C) on sweet potato flour were investigated. Flour treated with CaCl2 had higher amounts of ascorbic acid and β‐carotene (10.61–12.54 and 3.26–3.46 mg 100 g?1 wet basis, respectively) than that treated with NaHSO3 (9.47–11.47 and 3.05–3.43 mg 100 g?1 wet basis, respectively). Total phenolic content and water absorption index (wet basis) were highest at 65 °C when treated with NaHSO3 (10.44 mg 100 g?1 and 2.49 g g?1 respectively) and CaCl2 (9.52 mg 100 g?1 and 2.85 g g?1 respectively). Swelling capacity (wet basis) was highest at 60 °C when treated with CaCl2 (2.96 g g?1) whereas when treated with NaHSO3 (2.85 g g?1) it was highest at 55 °C. Freeze‐dried samples treated with NaHSO3 had higher lightness and total phenolic content while CaCl2‐treated samples had higher β‐carotene and ascorbic acid. The results showed that good quality flour could be produced after soaking in CaCl2 and dried at 65 °C.  相似文献   

12.
The binding of mutagenic pyrolysis products to cells of 50 yeast strains and their cell fractions was investigated. Cells of all yeast strains effectively bound 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). Cell walls (CW), and cell wall glucan and mannan (5 mg in each case) showed the highest binding of Trp-P-1 (50 μg ml?1); glucan adsorbed virtually all of the Trp-P-1. Cytoplasm also showed some binding but was much less effective. Glucans also bound well with 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3,8-dimethylimidazo 4,5-quinoxaline (MeIQX) much more than CW, but 2-amino-5-phenylpyridine (Phe-P-1) and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MelQ) were not effectively bound. The quantity of IQ, MeIQ, Phe-P-1 and MeIQX bound was dependent on the strain of yeast. The mutagenic pyrolysis products bound to cells were effectively extracted by aqueous methanol, ammonia (50 g litre?1) and alcohol, but not by water. The binding was pH dependent and inhibited by metal salts. When yeast cells were heated to 100° for 15 min, the binding of Trp-P-1 decreased by about 30% but Saccharomyces cerevisiae 50 heated to 100° did not differ much from untreated cells in its binding ability.  相似文献   

13.
‘Pontiac’, ‘Sebago’ and potatoes marketed under the general name of New potatoes were purchased from retail outlets in Sydney, Australia every 2 weeks over a 12-month period during 1982–83 to determine the change in composition over a season. Data are presented for water, vitamin C, starch, sugars (fructose, glucose and sucrose), dietary fibre, protein, fat, organic acids (malic, citric and oxalic acids), ash, carotenes, thiamin, riboflavin, niacin, potassium, sodium, calcium, magnesium, iron and zinc levels, edible weight and energy content. The level of vitamin C varied throughout the year from 10 to 23 mg 100 g?1 for ‘Pontiac’, 14 to 29 mg 100 g?1 for ‘Sebago’ and 16 to 32 mg 100 g?1 for New potatoes with the lowest values occurring in August to September (late winter to early spring) and the highest values in December to January (mid summer). Substantial variations also occurred in the water content, which was higher, and the level of starch and hence energy content, which was lower, during the cooler months of the year. Smaller changes were noted for niacin and thiamin which were lower and sugars which were higher during the winter period.  相似文献   

14.
In the traditional (kimoto) method of sake (Japanese rice wine) brewing, Saccharomyces cerevisiae yeast cells are exposed to lactate, which is produced by lactic acid bacteria in the seed mash. Lactate promotes the appearance of glucose-repression-resistant [GAR+] cells. Herein, we compared the resistance to glucose repression among kimoto, industrial, and laboratory yeast strains. We observed that the frequencies of the spontaneous emergence of [GAR+] cells among the kimoto strains were higher than those among the industrial and laboratory strains. The fermentation ability of a kimoto yeast (strain U44) was lower than that of an industrial strain (K701), as [GAR+] cells generally showed slower ethanol production. The addition of lactate decreased the fermentation abilities of the K701 strain by increasing the number of [GAR+] cells, but it did not affect those of the U44 strain. These results suggest that lactate controlled fermentation by promoting the appearance of [GAR+] cells in the industrial sake strains but not in the kimoto strains.  相似文献   

15.
以青岛啤酒酵母和高浓酵母为供试菌株,通过原生质体融合得到融合子。对融合子利用铜抗性初筛,利用耐压和发酵性能为指标进行实验室和100 L发酵复筛,并对融合子进行鉴定及遗传稳定性实验。结果表明:通过原生质体融合选育出的高浓菌株与青岛啤酒酵母菌株相比,表现出酵母数峰值高、降糖和还原双乙酰快的优势,且代谢风味物质组成与青岛啤酒酵母接近;经过连续使用8 代后,其总染色体DNA指纹图谱保持一致,证明该菌株的遗传稳定性高。  相似文献   

16.
The yeast ecosystem of Nem chua, a Vietnamese traditional fermented sausage naturally rich in medium‐chain‐length lipid‐derived flavouring compounds, was investigated to select biocatalysts able to produce the C10‐fatty acid‐derived aroma compound γ‐decalactone. The total number of yeast was about 5 × 104 to 4 × 105 CFU g?1, and eighty four different species were identified from morphological, physiological and 26S rDNA characteristics, with Candida sake and Candida haemulonii being found in all samples. Six strains able to produce γ‐decalactone from castor oil were selected, of which three Yarrowia lipolytica strains were able to produce between 1 and 2 g L?1 in our study. The strains produced the same amount from the acyl substrate under the form of ester or free fatty acid. Every strain degraded the product at the end of the culture. These high productions make them good candidates for industrial processes and confirm that traditional fermented foods are interesting bioresources for biocatalysts.  相似文献   

17.
This study was undertaken to determine the magnesium ion biosorption ability of the C. utilis and S. cerevisiae yeast species during cultivation in model media supplemented with magnesium. The mannoprotein and β-glucan content in the investigated yeast cell wall were analyzed because of the essential function of yeast cell wall structural components in metal ion binding. At the same time, an observation of yeast cells with the use of a transmission electron microscopy (TEM) was performed. The S. cerevisiae No. 1 yeast demonstrated the largest magnesium cation biosorption capacity. The magnesium content in biomass of S. cerevisiae No. 1 was about 16 mg Mg2+/g of dry substance after living cell incubation in MgSO4 solution and about 18 mg Mg2+/g of dry substance after pasteurized biomass incubation in YPD medium supplemented with magnesium ions. The tested yeast strains differed in mannoprotein and β-glucan content in the cell wall. The cell wall of S. cerevisiae 102, coming from YPD + Mg2+ medium, contained the greatest amount of glycoproteins (approx. 66 % adjusted to a total sugar basis). The cell wall of C. utilis ATTC 9950 yeast incubated under the same conditions was composed mainly of β-glucans (approx. 78 %) with prevailing β-(1,6)-glucans in this glucose polymer fraction (approx. 53 %). In S. cerevisiae No. 1 and C. utilis yeasts, higher degrees of magnesium ion binding were observed in the presence of higher β-glucan content in the cell wall structure, whereas in S. cerevisiae, 102 cells the magnesium ion adsorption was determined mainly on the grounds of mannoprotein presence. The process of yeast cell pasteurization increased the magnesium ion binding ability in the tested fungi strains as a result of cell wall structure loosening.  相似文献   

18.
In a survey carried out on 87 rotted fig fruits samples collected in the Apulia region of Italy, the authors isolated 126 Fusarium strains identified as F. ramigenum (69 strains), F. solani (49), F. proliferatum (five) and three not identified. Investigation on the fertility of the strains belonging to F. proliferatum and F. ramigenum revealed that only strains of F. proliferatum were fertile. The identity of F. ramigenum strains was confirmed by sequencing a portion of the translation elongation factor-1α gene. When Fusarium species were analysed for their toxigenicity, 37/69 strains of F. ramigenum produced fusaric acid (FA) up to 525 mg kg?1; 30 strains produced beauvericin (BEA) up to 190 mg kg?1; 60 strains produced fumonisin B1 (FB1) and fumonisin B2 (FB2) up to 1575 mg kg?1 of total FBs; and two strains produced fusaproliferin (FUP) up to 345 mg kg?1; all five strains of F. proliferatum produced FA at low levels; two strains produced BEA up to 205 mg kg?1; one strain produced FB1 and FB2, 1100 and 470 mg kg?1, respectively; and one strain produced FUP, 820 mg kg?1; F. solani (30 strains) produced FA, 13 strains up to 215 mg kg?1. Few fungal extracts showed high toxicity toward brine shrimp larvae and in some cases in relation to BEA and FA content. A pathogenic assay on fig fruits showed that all three species were pathogenic, with higher virulence of F. ramigenum. These data report for the first time the production of BEA and FB1/FB2 by F. ramigenum and show that it is a main agent of fig endosepsis in Apulia and can contribute to fumonisin contamination of fresh and dried figs.  相似文献   

19.
The cell walls of parenchyma, rind and vascular bundle fractions of pearl millet (Pennisetum glaucum (L) R Br) were isolated from two brown midrib mutants (bmr) 5753 and 5778 and from their normal (N) near-isogenic line. The cell wall content of parenchyma was lower than that of vascular bundle which, in turn, was lower than that of rind. The amounts of ferulic and p-coumaric acids released by NaOH treatment of the cell walls were in the ranges 3-7 mg g?1 and 2-26 mg g?1, respectively. Parenchyma cell walls of the N line had the highest content of p-coumaric acid (26 mg g?1). This content of p-coumaric acid in the N line contrasts with that of bmr 5753 parenchyma (2 mg acid g?1 walls) and bmr 5778 (7 mg acid g?1 walls). The concentration of p-coumaric acid was highest in parenchyma cell walls that had been found to be the least digested. Parenchyma, rind and vascular bundle cells walls of the N line had much higher ratios of p-coumaric acid to ferulic acid than the mutants; rind and vascular bundle walls were less digestible than parenchyma. Small amounts of truxillic acid dimers were released by NaOH from the parenchyma walls of bmr 5778. Treatment of parenchyma, rind and vascular bundle cells walls with purified ‘driselase’ (containing xylanases and cellulases) released p-coumaroyl and feruloyl trisaccharides. Between 25 and 53% of the ferulic acid that was released by the NaOH treatment could be accounted for as feruloyl trisaccharide, but only 1-19% of the p-coumaric acid was accounted for as p-coumaroyl trisaccharide.  相似文献   

20.
An HPLC method has been used to separate and determine quality-related chemical components in Zhenong-xiangya and Zhenong-cuiliu, two special green teas from Zhejiang, China. Seventeen or eighteen amino acids and five catechins were detected. Theamine was the major amino acid by far, its content reaching 37.7% and 54% of the total amino acids in these teas, respectively. The catechin content was 154.4 mg g?1 in Zhenong-xiangya and 170.7 mg g?1 in Zhenong-cuiliu. Caffeine contents in the teas studied were all above 75 mg g?1 which was much higher than those previously reported in green teas. The vitamin C contents were all about 2 mg g?1. Seven peaks were resolved in the HPLC profiles of the flavonoid extracts of the two teas and three of them were identified as rutin, myricetin and quercetin using reference compounds.  相似文献   

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