Seed inoculum

The above sterilized medium was inoculated with 11 liters of seed inoculum having a bacterial count of approximately 20 billion per cc. The tank was fermented at 37°C without pH adjustment, aeration, or other modification for 14 hours at the end of which time 320 cc of 50% dextrose was added. After this the pH was adjusted to 7.0 at 15 minute intervals with 5.0 N sodium hydroxide. The volume of sodium hydroxide required for neutralization was noted and 115% of this volume of 50% dextrose solution added after each pH adjustment. At the end of about 8 hours the bacterial count had ceased to increase and the fermentation was terminated. At this time the fermentation medium contained approximately 1,000 units of streptokinase per cc. 

Batch fermentation is the most widely used method of amino add production. Here the fermentation is a dosed culture system which contains an initial, limited amount of nutrient. After the seed inoculum has been introduced the cells start to grow at the expense of the nutrients that are available. A short adaptation time is usually necessary (lag phase) before cells enter the logarithmic growth phase (exponential phase). Nutrients soon become limited and they enter the stationary phase in which growth has (almost) ceased. In amino add fermentations, production of the amino add normally starts in the early logarithmic phase and continues through the stationary phase. 

For economical reasons the fermentation time should be as short as possible with a high yield of the amino acid at the end. A second reason not to continue the fermentation in the late stationary phase is the appearance of contaminant-products, which are often difficult to get rid off during the recovery stage. In general, a relatively short lag phase helps to achieve this. The lag phase can be shortened by using a higher concentration of seed inoculum. The seed is produced by growing the production strain in flasks and smaller fermenters. The volume of the seed inoculum is limited, as a rule of tumb normally 10% of the fermentation volume, to prevent dilution problems. 

Evaluated the effect of environmental factors on hydrogen production using mixed culture. Successfully enriched naturally available mixed seed to culture hydrogen producing bacteria. Enhanced the hydrogen production through preheat treatment of seed inoculum at 70-90°C for 15 - 20 minutes followed by repeated heat treatment of settled returned sludge. 

High rates of application of Mo can be detrimental to Rhizobia in the seed inoculum used in some pelleting procedures or can cause seedling injury under certain growing conditions (Sedberry, et al., 1973). 

Specific procedures exist for storing (16,17) and propagating microorganisms to obtain reproducible fermentations. The stock culture is stored frozen (<—80°C) or freeze-dried. To prepare the inoculum (seed) mixture, an aUquot is taken and grown in consecutive soHd or Hquid cultures of increasing volume. The volume of the last step, the seed fermentor, is typically 4—12% of the main fermentor volume. 

Impf-fliissigkeit, /. inoculation lymph, vaccine lymph, -kristall, w. seed crystal, -mittel, n, inoculating agent, inoculum, inoculant vaccine, -stift, m> inoculating pencil, -stoff, m. inoculating material, inoculum vac-... 

After seeding the nutrient medium with the preformed inoculum previously described, the mixture was subjected to agitation and aeration under aseptic conditions for 72 hours at 27°C to 28°C for the first 24 hours, then at 25°C to 26°C for the next 48 hours during this period, the pH was in the range of 6.4 to 6.8. Aeration was accomplished by cultivation under submerged conditions at an air flow rate of one volume of air per volume of medium per minute. After termination of the process, the mycelium was removed by filtration and the filtered broth found to contain 450 7of oleandomycin per ml of solution. 

The seed flash was incubated for 24 hours at 32°C on a reciprocating shaker after which it was used as an inoculum for a 20 liter seed fermenter in the amount of approximately 5%. the 20 liter seed fermenter contained a sterile medium consisting of ... 

It is very simple to perform batch fermentation in a small flask with a volume of say 200 ml. Now our target is to use a 2 litre B. Braun fermenter. All accessories are shown in Figure 10.5. The fermentation vessel only, as shown in Figure 10.6, with about 250 ml of media without any accessories but with some silicon tubing attached with a filter for ventilation is autoclaved at a 131 °C for 10 minutes at 15psig.9 After that, the system is handled with special care and all accessories attached. Media is separately sterilised and pumped into the vessel. Inoculum is transferred and the batch experiment is started right after the inoculation of seed culture. An initial sample is withdrawn for analysis. 

The importance of including soil-based parameters in rhizosphere simulations has been emphasized (56). Scott et al. u.sed a time-dependent exudation boundary condition and a layer model to predict how introduced bacteria would colonize the root environment from a seed-based inoculum. They explicitly included pore size distribution and matric potential as determinants of microbial growth rate and diffusion potential. Their simulations showed that the total number of bacteria in the rhizosphere and their vertical colonization were sensitive to the matric potential of the soil. Soil structure and pore size distribution was also predicted to be a key determinant of the competitive success of a genetically modified microorganism introduced into soil (57). The Scott (56) model also demonstrated that the diffusive movement of root exudates was an important factor in determining microbial abundance. Results from models that ignore the spatial nature of the rhizosphere and treat exudate concentration as a spatially averaged parameter (14) should therefore be treated with some caution. 

Saprophytic, dark pigmented fungi such as Alternaria spp. can infect a wide range of plant species, especially tissues that are exposed to other biotic or abiotic stressors and older and senescing plant tissues. Also, wet weather conditions favour attack by Alternaria spp. Inoculum of Alternaria and potentially production of altemariol is further enhanced when cereal straw and stubble is left on the soil surface and not sufficiently incorporated into the soil after harvest (direct seeding and minimum tillage systems). 

Earlier studies indicated that wheat cultivars responded differently to these organisms (15). If necessary, it should be possible to develop resistant varieties, especially When we know the mechanisms of plant uptake and mode of action of the toxin within the plant. One biological control may be the development of a TOX-negative inoculum for seed treatment. These bacteria may act like other rhizobacteria, which are known to increase plant growth, apparently by displacing nonbeneficial bacteria in the plant rhlzosphere (14). 

---