Filamentous microorganisms

Fig. 3-6 Microfossils of several filamentous microorganisms. Bitter Springs Formation, Central Australia. Dated at 0.85 Gyr. (Courtesy William Schopf.)...

Fig. 10.4 Fossilized cellular filamentous microorganisms (two examples of Primaevifilum amoenum). They are 3.456 billion years old and come from the Apex chert region in northwestern Australia. As well as the original images, drawings and the Raman spectra and Raman images, which indicate that the fossils have a carbonaceous (organic) composition, are shown. With kind permission of J. W. Schopf...

Storm, P.F. Jenkins, D. Identification and significance of filamentous microorganism in activated sludge. 54th Annual Conference of the Water Pollution Control Federation, Detroit, Michigan, 1981. 

The industrial production of penicillin by Pfizer in 1943 transformed the chemistry of natural products. Microbiology became its field and pharmaceutical research became its leading trend. The main driving force behind the research of the chemistry of natural products was and still remains to be human health care. Since the advent of antibiotics, many sources of natural chemicals, such as plants, fungi and bacteria, have been searched for antibacterials, anticancer products, immuno-suppressors and chemicals that affect the human psyche. This research was so successful that, even today, more than half of all pharmaceuticals are either natural products or derived from, or inspired by them. The market of antibiotics alone was ca. US 30 billion in 2005. The majority of antibiotics is produced by submerged fermentation of filamentous microorganisms such as soil prokaryotic actinomycetes and eukaryotic moulds, ascomycetes. 

Depending on process parameters, culture age and genetic make-up, filamentous microorganisms in an industrial fermenter can either grow as free mycelia or as mycelial aggregates — pellets or flocks (Fig. 2). Of course, this polar definition is far from reality all kinds of intermediate morphologies exist between free unassociated mycelia, loose flocks and dense pellets. The... 

The issue of the relation between the form and the productivity in filamentous microorganisms is of utmost importance for a variety of reasons ranging from purely fundamental to purely economic. This importance resulted in the multiplicity of research timely published and reviewed. However, the field remains descriptive but not predictive. It is not yet possible to make a molecular model or algorithm, where one uses morphological parameters to come up with the output and the assortment of metabolites. 

Strain development is the prerequisite for the development of efficient processes for the production of natural products in filamentous microorganisms. Although the morphology of filamentous growth can be... 

One way or another, the new techniques of genetic manipulation and analysis will find their way into industrial production of more efficient biologically active novel natural products from filamentous microorganisms. This process is already under way. The major pharmaceutical companies are at the forefront of progress in applying state-of-the-art techniques to strain and product development. 

Y. Fukuzawa and K. Kagawa, Cooperation of humoral and cell-medlated Immunities against experimental candidiasis and cryptococcosis, in Filamentous Microorganisms (T. Arai, ed) Japan Scientific Societies, Tokyo, (1985) 247-253. 

I. Kubo and M. Himejima, Anethole, a synergist of polygodial against filamentous microorganisms, J. Agric. Food Chem., 39, (1991) 2290-2292. 

Figures 4 and 5 show that aeration affects the parameters of the culture. For the three air flows tested, moistened air gives best activities than dry air. The higher xylanase productions appear at 0.1 1/min moistened air after 7 days (4,000 U/g) with the mycelial inoculum (Fig. 4) and after 12 days (2,300 U/g) with the conidial inoculum (Fig. 5). The xylanase production increases during days 3-7 in all the cases. However, during days 7-12, the xylanase production increases slowly or decreases. Maybe, this weak increase of xylanase activity after the seventh day is caused by the effects of forced aeration. Indeed, this situation did not appear in passive aeration. It has clearly established in submerged fermentation that P. canescens is very sensitive to hydrodynamic stress generated by aeration and mixing of the medium [21-23]. A lowering stress due to aeration would be beneficial as well for the synthesis of several enzymes by filamentous microorganisms in general as for the synthesis of xylanase by P. canescens in particular [21-23].

Streptomyces species and other filamentous microorganisms show a rapid growth phase that is not strictly exponential, because of the polar growth of the hyphae, followed by a transition phase that leads to a stationary phase, which in some species is rapidly followed by massive lysis of the culture while in others may be prolonged for a few days before lysis occurs (Kolter et al. 1993). 

Lesage-Meessen, L., Delattre, M., Haon, M. et al. (1996) Method for obtaining vanillic acid and vanillin by bioconversion by an association of filamentous microorganisms. Patent WO %/08576. 

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