Occurrence of fungi on deteriorated old dluwang manuscripts from Indonesia.

• Diverse fungal species deteriorating old dluwang manuscripts in Indonesia.
• The isolated fungi were xerophiles and able to grow on cellulosic material.
• Aspergillus and Penicillium were the most frequent genera isolated.
• Strains of Aspergillus versicolor (10), Penicillium citrinum (7), Aspergillus flavus (5), and Penicillium rubens (5) were commonly isolated.

Dluwang was made from the bark of the paper mulberry (Broussonetia papyrifera Vent.). Old Javanese manuscripts were handwritten on dluwang. Fungi samples from deteriorated dluwang manuscripts from the libraries of royal palaces in Indonesia and from the faculty library of Universitas Indonesia were collected by using cotton swabs and adhesive tape. Fungal isolates were obtained by the culture-dependent method. Identification of 38 fungal isolates was carried out by the molecular method using the internal transcribed spacer (ITS) regions of ribosomal DNA. Phenotypic description of the isolates was obtained by classic culturing and direct microscopic observation. The results showed that fungi from the genera of Aspergillus and Penicillium were commonly found on old dluwang manuscripts. According to the molecular identification, species obtained were Aspergillus awamori, Aspergillus clavatus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus jensenii, Aspergillus niger, Aspergillus pulvericola, Aspergillus ruber (Eurotium rubrum), Aspergillus versicolor, Penicillium citrinum, Penicillium oxalicum, Penicillium rubens, Pseudocercospora chiangmaiensis, and Trichoderma longibrachiatum. The isolated fungi were xerophilic and cellulolytic in nature. All isolates were able to grow on dluwang paper, 29 isolates (76%) were able to utilize carboxymethyl cellulose (CMC), and 18 isolates (47%) were able to utilize CMC and microcrystalline cellulose (MCC). The present study showed that the deterioration of the written heritage was potentially caused by diverse fungi.