Journal des bioprocédés et des biotechniques

Air-conditioned areas of a museum were monitored for the presence of total microbes in the air. The results were evaluated based on a Brazilian resolution that regulates accepted contamination levels in air-conditioned spaces, as well as based on the parameters from the World Health Organization. The results indicated low levels of bacterial and fungal populations in four distinct spaces, with total counts smaller than 50CFU m-3. These results, compared to the monitoring performed in the outside area of the museum indicated a very low internal to external count ratio, the highest one around 0.131, a value far beyond the acceptable limit of 1.5, as predicted by the Brazilian legislation. Even though those values clearly indicate low levels of contamination for human comfort, in the spaces monitored, the marked presence of fungi from the genera Cladosporium, Aspergillus and Penicillium deserve particularly attention due to their possible cellulolytic activity. The spaces are permanently controlled for their temperature and relative humidity levels, to be used as a permanent repository for scientific and historical documents in Brazil, and the presence of these potential cellulose-degrading microbes can markedly jeopardize the effective occupation of the areas due to their biodeterioration effects.