Microbiological process

Details Microbiological process Microbiological process

1996-08-09

1999-08-10

Weber, Jon P.

Chemistry: molecular biology and microbiology

Micro-organism, per se ; compositions thereof; proces of...

Fungi

4352547, 435261, 435911, 426 61, 426665, 424 933, 424 935, C12N 100, C12N 102, C12N 114, A23C 912

Patent

active

059358416

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

THIS INVENTION relates to a microbiological process.
It is known how to grow filamentous microorganisms especially eukaryotic microorganisms, for example fungi in industrial processes, for example Aspergillus species, especially Aspergillus oryzae and Aspergillus niger are known for the production of citric acid; Penicillium species, especially Penicillium chrysogenum are known for the production of penicillin and Fusarium, especially Fusarium graminearum is grown for use in the manufacture of food.
It is desirable that the organisms should grow rapidly in the culture, as this increases the throughput per unit reactor volume.
In the culturing of such microorganisms hyphal branching occurs, and there may be a tendency for the population to become increasingly branched as culturing continues if the original microorganisms show little branching. This may present problems in the case of a product intended as food, leading to its having an unsatisfactory texture.


SUMMARY OF THE INVENTION

This invention comprises a method of modifying a filamentous microorganism which comprises culturing a sample of desired morphology until a substantial proportion of the culture population diverges from the desired morphology, selecting from the culture at that stage at least one microorganism exhibiting the desired morphology, and repeating said culturing with the selected microorganism at least once for example at least 3, and suitably at least 5 times.
It will be realised that the microorganisms of desired morphology are not identical and will diverge in size, and number or proportion of branching points.
Similarities in morphology are suitably judged in terms of numbers of filament ends per unit length of the total mycelium ie the hyphal growth unit length, though other criteria for assessing morphology may be used if desired.
It is believed that as the number of repeated culture and selection stages increases the selected microorganisms will increase in growth rate relative to their more normally branched variants and this will give them a selective advantage. Such an effect would allow an industrial process exhibiting unstable morphology to be continued longer thus increasing the availability of plant by reducing the proportionate amount of down-time and reducing the shut-down and start-up costs associated with operating plant over a period of time.
By "unstable morphology" is meant that on long continued culturing variants of undesired morphology eventually amount to an industrially unacceptable proportion of the total organisms present.


BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 Flow diagram showing the history of the chemostat cultures from which variants were isolated.
FIG. 2 Competitions between chlorate-resistant ( , ) and chlorate-sensitive ( , ) strains of F. Graminearum grown in glucose-limited chemostat culture at a dilution rate of 0.18 h.sup.-1.
FIG. 2(a) competition between A3/5 (closed symbols) and A21-XS (open symbols),
FIG. 2(b) competition between A3/5 (closed symbols) and A23-S (open symbols),
FIG. 2(c) competition between A3/5 (closed symbols) and A24-S (open symbols),
FIG. 2(d) competition between A23-S (open symbols) and A24-S (closed symbols).
FIG. 3 Time-course trends for dilution rate and the proportion of colonial variants observed during continuous culture.
FIG. 4 Competitions between F. Graminearum A3/5 and colonial variants A22-1 (o) and between A23-S and colonial mutant A22-1 ( ) grown in glucose limited chemostat culture at a dilution rate of 0.18 h.sup.-1.


DETAILED DESCRIPTION OF THE INVENTION

The invention is suitably carried out with Fusarium, for example Fusarium solani or Fusarium oxysporium but especially Fusarium graminearum. A food-approved sample of this organism is deposited with the Commonwealth Mycological Institute, (IMI) Ferry Lane, Kew, Richmond, Surrey England under deposit number CMI (formerly IMI) 145425 and with the American Type Culture Collection, 12301 Parklawn Drive Rockville, Md. 20852, USA under number ATCC 20334.
Suitable condition

Affiliated with

Also associated with

Rating

Microbiological process does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Microbiological process, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microbiological process will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1119464