Correlative characterization of changes in hyphal morphology during xylanase production in submerged culture by Thermomyces lanuginosus SS-8
S Shrivastava, P Shukla, K Mukhopadhyay
conidia, hyphae, submerged cultivation, xylanases
S Shrivastava, P Shukla, K Mukhopadhyay. Correlative characterization of changes in hyphal morphology during xylanase production in submerged culture by Thermomyces lanuginosus SS-8. The Internet Journal of Microbiology. 2007 Volume 4 Number 2.
Most of the industrial enzymes are produced by filamentous fungi which often display different morphological forms during their growth in different stages of submerged cultivation as well as in solid media. In the present study the characterization in hyphal morphology of indigenous xylanase producing
Xylanases (Endo-1,4-Beta-xylanase or XYN, EC 220.127.116.11) are glycosidase which catalyzes the endohydrolysis of 1,4-β-D-xylosidic linkages in backbone of complex plant polysaccharides xylan. Filamentous fungi produce number industrial enzymes which have wide variety of applications (Kirk et.al 2002; Sharma et.al 2001) and hence studies on filamentous fungi have always been of prime importance. Among microorganisms filamentous microbes are one of the most prolific producers of extra cellular enzymes and they are also widely used for industrial enzyme production. Some other xylanase producing organisms are
In the present study different growth forms of
It is a widely distributed thermophilic fungus commonly isolated from self heating masses of organic debris (Emerson, 1968). It is classified as a Deuteromycetes (imperfect fungus) that is unicellular or septate and reproduces asexually by forming aleurioconidia (Singh et al., 2003). This organism is non-cellullolytic and it has been reported that it probably grows commensally in composts with cellulolytic fungi by utilizing some of the sugars generated by the enzymes of these fungi and also by using their mycelial breakdown products (Deacon, 1997).
Initially the colonies of
Despite considerable progress in understanding the different stages in hyphal developments during enzyme production by various morphological forms of filamentous fungi the present hyperxylanolytic isolate
Materials and methods
Microorganism and growth conditions
Microscopy & Image analysis
The microscopy and image analysis was carried out with the help of Leica FW 4000 (Leica Stereozoom at X3.2.)Light microscope at 40X and 100X magnifications. One milliliter samples of
Enzyme Activity Assay
Xylanase activity was routinely determined by mixing 100µl of enzyme solution with 500µl of Oat spelt xylan (2%, w:v) in 50mM Citrate buffer, pH 6.5 at 50°C for 10 min. The release of reducing sugar was measured using the dinitrosalicylic reagent method (Miller, 1959). Xylose was used as the standard. Xylanase activity was expressed as µmoles of reducing sugar formed per milliliter of enzyme solution per minute, i.e. as IU ml -1 min -1 .
When the colonies completely mature, they appear blackish brown with dark brown globbose aleurioconidia of diameter size 10µm to 11µm. The hyphal diameter at this stage is about 3µm
The changes in hyphal width with respect to different colony color have been plotted in
From the study it was concluded that as fungal cells mature the enzyme production increases. There was no enzyme present in production medium upon 24hr incubation. Thus suggesting that white colony with budding conidia could not produce any enzyme. Subsequent incubation for 48, 72, 96, 120, 144 and 168 hr showed gradual increase in enzyme activity. It was seen that as conidia matures its capacity of enzyme production increases and amount of enzyme produced shows a measurable increase with the change in colony color from yellow to brown.
The increase in hyphal diameter from white to yellowish colony is by a factor of 2. The complete increase in hyphal diameter from white to blackish brown colony is by a factor of 3. The yellow color colony of the organism is unique to this novel form as no earlier literature reports this feature. Previous literatures suggest the purplish or green colony which is absent in this strain.
We gratefully acknowledged the support from Department of Agriculture, Government of Jharkhand & Sub-Distributed Information Center (BTISnet SubDIC) of Department of Biotechnology, Government of India in the form of R & D Grants for our department.