Aspergillus niger is one of the most active cellulolytic fungi. The roll of drawings in the above picture is mainly infested by A. niger and Chaetomium sp. as identified from the cultures isolated from the deteriorating inner-side of the roll. This culture was maintained on potato dextrose agar slants.
Following are the digital pictures of the portions of the slides that were studied under a compound microscope.
Aspergillus niger is ubiquitous in soil and is commonly reported from indoor environments.
Cellulase production by Aspergillus niger on lignocellulosic substrates is reported in both submerged (SmF) and solid State (SSF) Fermentations. Cellulases are the group of hydrolytic enzymes Filter paperase (FPase), Carboxymethylcellulase (CMCase) and -glucosidase (BGL) and are responsible for release of sugars in the bioconversion of the paper into a variety of products which is the cause of loss of drawing along with the paper.
P.S. (post scriptum)
Aspergillus niger is included in Aspergillus subgenus Circumdati, section Nigri. The section Nigri includes 15 related black-spored species that may be confused with A. niger, including A. tubingensis, A. foetidus, A. carbonarius, and A. awamori.
Sm/SS Fermentation–infestation due to ligno- cellulosic substrate is obvious ,could be eradicated,with the use of Thymol or in sunlight I think.
In this particular case, the substrate is not an ordinary paper, but chemically treated paper to make blue lines of an engineering drawing. So, it is not so simple, as we know that thymol reacts with many organic pigments and dyes.The chemical nature of blue lines is inherently sensitive to sunlight. Blue lines are extremely sensitive to light and we see innumerable drawings gone completely blank because of fading.
Things and issues in the field of conservation are not as easy as they seem. Moreover, in the process of all this study, we learn and understand life, ecology and other more important issues much better.