Teflon 98 Yeast

Alcohol Sensor. On-line measurements of ethyl alcohol concentration in culture broth are required in fermentation industries. A microbial electrode consisting of immobilized yeasts or bacteria, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the determination of methyl and ethyl alcohols(7). 

Akyilmaz and Dinijkaya [55] Wine Beer Liquor Alcohol oxidase in C. tropicalis cells/cells over a Teflon membrane and immobilised with glutaraldehyde yeast cells (Saccharomyces ellipsoideus)/micro-orgamsms Clark type 02 electrode -... 

Li et al. [37-39] described the use of the bacterial species Bacillus subtilis and Bacillus licheniformis entrapped between a polycarbonate membrane and a Teflon-covered DO probe. The differences between the steady-state signals before and after exposure to the test samples were used as a measure of the sample BOD levels. Riedel et al. [32-33] described the use of the yeast Trichosporon cutaneum, or both T. cutaneum and B. subtilis, sandwiched between a dialysis membrane and a polyethylene-covered DO probe. In these cases, the sensor response times were speeded up by measuring the initial rates of change of the signals. In this way, measurements could be made within 30 s rather than within 15-20 min for the steady-state approach [33]. 

The chemostat vessel was a modified 500-mL Virtis fermentor with a teflon impeller. The medium consisted of 350 mL MSM containing alachlor (100 mg/L), glucose (100 mg/L), and yeast extract (50 mg/L). The chemostat was inoculated with 20 mL of soil perfusate, the inoculum was allowed to grow to stationary phase as a batch culture,... 

Yeast biomass was freeze-dried and grounded. Fatty acid extraction and preparation of methyl esters were carried out according to Lepage and Roy [25]. Samples (100 mg) were transmethylated with 5 ml of methanol/acetyl chloride (95 5 v/v). The mixture was sealed in a light-protected Teflon-lined vial under nitrogen atmosphere and heated at 80 °C for 1 h. The vial contents were then cooled, diluted with 1 ml water, and extracted with 2 ml of n-heptane. The heptane layer was dried over Na2S04, evaporated to dryness under nitrogen atmosphere and redissolved in heptane, which contained the methyl esters. 

Christen et al. (2004) developed an SLM system for the extraction of EtOH during semicontinuous fermentation of Saccharomyces bayanus. The membrane was a porous Teflon sheet as support, soaked with isotridecanol. The removal of EtOH from the cultures led to decreased inhibition and, thus, to gain in conversion of 452 g/1 glucose versus 293 g/1 glucose without extraction. At the same time, the EtOH volumetric productivity was enhanced 2.5 times, due to an improvement of yeast viability, while the substrate conversion yield was maintained above 95% of its theoretical value. In addition to these improvements in the fermentation performances, the process resulted in EtOH purification, since the separation was selective toward microbial cells and carbon substrate and likely selective to mineral ions present in the fermentation broth. For PV, a concentration of EtOH four times greater was obtained in the collected permeates. 

Yamane T, Matsuda M, Sada E. Application of porous teflon tubing method to automatic fed batch cultuie of microorganisms. II. Automatic constant Value control to fed substrate (ethanol) concentration in semibatch culture yeast. Biotechnol Bioeng 1981 23 2509. 

Carefully measured 2.000-g portions of the powdered yeast are placed into 20-mL headspace vials and diluted with either 10 mL of deionized water or 10 mL of deionized water containing 2 pg of indole. The vials are tightly capped using Teflon-faced septa and then vortexed or otherwise mixed well to suspend all of the dry material. They should then be placed in a thermostatted oven or waterbath at about 40°C before analysis for indole by headspace SPME GC/MS using the ion at m/z 117 for quantitation. At least two sets of vials are prepared for each sample—the first is used to determine the peak area of the indole in the native material and the second to measure the sum of the peak areas of the native indole plus the amount of indole added to the sample as a standard. The difference between the two sets of data can be used to calculate a response factor for the indole standard, and Anally the amount of native indole can be calculated. Indole in dry yeast can be measured accurately between 50 ppb and 10 ppm using headspace standard addition methods with a 100- J,m PDMS fiber. 

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