From sterilized medium

Fig. 4.6 Cyclic voltammograms of a mediator-producing bacterial suspension fed glucose at time 0 (black line), and after 30 min (red line) and 120 min (green line). Arrows indicate peaks while dashed lines that cross between oxidation and reduction peaks intersect the x-axis at the formal potential of the redox couple. The peak at -170 mV disappeared when bacteria were washed by centrifugation, but the peak at 180 mV never disappeared. There were no peaks observed from sterile medium. [From Rabaey et al. (2004), reprinted with permission of the American Society for Microbiology.]...

Inoculum Preparation Stage Two batches of inoculum of about 50 gallons each are prepared by the following method A 25 ml inoculum (from the germination stage) is transferred to each of four 2-liter flasks, each containing 500 ml of the sterile medium utilized for germination. The flasks and contents are incubated for 5 days at 28°C on a rotary shaker (280 rpm, 2 inch stroke). 

Tank fermentation of Micromonospora inyoensis — Germination stage 1 Under aseptic conditions, add a lyophilized culture (or cells obtained from a slant culture) of M. inyoensis to a 300 ml shake flask containing 100 ml of the following sterile medium ... 

Figure 1. Open circuit potential vs. time in sterile medium and in medium with bacteria (a) platinum, (b) 304L stainless steel. (Reprinted from Ref 1 with permission from NACE International.)...

It requires less steam by recovering heat from the sterilized medium. As a result, it also requires less cooling water. 

The following example from US Patent 2,602,769 illustrates the preparation of 17-hydroxycorticosterone (compound F) from ll-desoxy-17-hydroxycorticosterone (compound S). A medium was prepared from 0.5% peptone, 2% dextrose, 0.5% soybean meal, 0.5% KH2P04, 0.5% sodium chloride and 0.3% yeast extract in tap water. To 200 ml of this sterilized medium was added an inoculum of the vegetative mycella of Cunninghamella... 

Fermentation stage Aseptically transfer 500 ml of the medium obtained from Germination stage 2 to a 14-1 fermentation tank containing 9.5 I of the following sterile medium ... 

If it is necessary to refill the dispensing pressure vessel during filtration it is important that the pressure above the membrane filter does not fall or contamination may result. To avoid such a pressure fall valves may be fitted. Foot operated systems are available from Schleicher and Schuell which allow the flow of liquid to be interrupted at regular intervals this is very useful when filling 100 ml bottles from an otherwise continuous flow of 10 1 of sterile medium. However, we have found the system cumbersome to use and we... 

The biologically mediated emission of Po from a culture solution insulated with a sea sediment extract was observed. The emitted Po compound was considered to be lipophilic because it collected in organic solvents. Microorganisms are responsible for the emission of volatile Po compounds because no volatile compounds of Po were formed in a sterile medium. There exists an argument for the existence of a biotic source for atmospheric Po in the environment, which possibly originates from abiotic sources. The emission behavior of both Po and S in the culture experiments was compared. The chemical form of the emitted Po is not known, but it was emitted with dimethyl sulfide. A volatile Po compound was formed when methylcobalamin was used in the experiments. 

Solubility of Exocellular Nickel Complexes in Soil. To identify those complexes most important in mobilizing Ni in soil, the filtrates (<0.01) of the exocellular media from 20 representative bacterial cultures and all fungal cultures were passed through a column of the soil from which the organisms were isolated and the solubility, and chromatographic and electrophoretic properties of Ni in sterile water, sterile medium and exocellular medium were compared before and after elution through soil. 

There are two general approaches, wet tests and aerosol challenge tests. Wet tests consider penetration of microorganisms in liquid suspension into sealed containers usually previously filled with sterile medium. The basic assumption is that the most vulnerable route for penetration of liquid filled containers by microorganisms is in the event of a continuous liquid film or bridge forming between the outside and the inside of a container. Aerosol challenge tests are less critical than wet tests and should be applied only when total exclusion of moisture from the containment system can be ensured by secondary barriers. 

Decant PBS from sterilized stock solution of Cytodex 3 and replace with growth medium (1 g to 30-50 ml). Add Cytodex 3 to spinner vessel to give a final concentration of 2 g H (use in range 1-3 g H). 

Consideration should be given to validating the ability of the medium used to grow micro-organisms recoverd from environmental monitoring or from sterility testing. 

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