DOI: 10.22184/1993-7296.FRos.2026.20.2.150.159
Bacterial cellulose (BC) is a promising natural biomaterial considered as an alternative to the synthetic polymers for medical and pharmaceutical applications. The BC treatment protocols are aimed at removing any microbial producers and their metabolic residues. This paper explores the possible use of ultraviolet laser irradiation for additional BC treatment and application of the laser-­induced fluorescence (LIF) spectroscopy to monitor its microbial contamination. The BC treatment protocol with a maximum treatment period of 30 days with 0.1 M NaOH and subsequent ultraviolet treatment was considered. The LIF spectra were recorded in the excitation wavelength range of 220–290 nm. For a more accurate interpretation of the results, the same samples were examined using the laser scanning microscopy (LSM) method. The results have demonstrated that the alkali-­treated BC samples show the signs of tryptophan and tyrosine fluorescence, thus indicating the available microbial residues. Moreover, the LSM analysis has revealed the DNA-containing bodies with the dimensions of 1–2 µm after alkaline treatment. The ultraviolet irradiation of BC with a total dose of 12 J/cm2 has significantly reduced the density of such “bodies”, as well as the relevant tyrosine and tryptophan signals, but has not eliminated them completely. The ultraviolet laser irradiation at a wavelength of 240 nm leads to the photodegradation of the remaining producer cells and facilitates their removal, as confirmed by the LIF spectroscopy and confocal microscopy.