## 1 Introduction  
Cellulose is the most widespread biopolymer in the world. Although commonly most used is the one from plants, other organisms, such as algae, fungi, and bacteria, can produce it [1]. In structural terms, bacterial cellulose (BC) is compatible with that of plant origin, additionally being free from impurities in the form of lignin and hemicellulose. In the face of global environmental crises, including that caused by extensive deforestation, BC is an attractive alternative as a source of this biopolymer. Bacterial cellulose exhibits unique properties, such as complex nanostructure, high crystallinity, retention of large amounts of water, and high mechanical strength [2]. These material properties are the reasons for the high interest in developing BC-based composites and derivatives that could be applied in many fields, such as the electronics, food, and paper industries, as well as the medical and veterinary fields [3; 4]. Many species of bacteria have the ability to produce bacterial cellulose, including mainly _Acetobacter_ spp., but also _Agrobacteriumium tumefaciens_, _Rhizobium_ spp., and _Sarcina ventriculi_[5]. The most efficient BC producer is _Komagataeibacter xylius_, an aerobic Gram-negative bacteria. The production of bacterial cellulose by these bacteria can be affected by various factors, i.e., the bacterial strain potential, cultivation method, carbon, nitrogen source, media acidity, or temperature [6; 7]. BC synthesis by _K. xylius_ can be performed in a relatively wide pH range between 3.0-7.0 and a temperature of 25-30 \({}^{\circ}\)C. However, the optimal conditions depend on the specific requirements of the bacterial strain [8; 9]. Despite many years of intensive research, the cost of cultivation media is still the most limiting factor for the wider use of BC in industry. Currently, the possibility of solving this issue is combined with using by-products and waste from the food industry and agricultural production as feedstocks to prepare cultivation media. Nowadays, the food industry generates a significant amount of waste that can be a valuable source of ingredients for cultivation media for _K. xylius_[5; 10]. For example, during sugar production by the processing of sugar cane or, on a smaller scale, sugar beets, significant amounts of molasses and pulp are produced [11; 12]. Moreover, processing fruits, vegetables, and grains generates pomace containing significant amounts of various poly- and oligosaccharidesrides [13; 14]. In addition, the waste from the dairy industry, mainly whey, is also rich in various types of valuable oligosaccharides [15]. This biomass contains a significant number of saccharides, such as starch, sucrose, and lactose. However, due to the lack of appropriate metabolic pathways and enzymes, these poly- and oligosaccharides in the unchanged form are not available as carbon sources for _K. xylius_ cells in the BC synthesis process. The solution to this inconvenience may be the usage of different enzymes of microbial origin to liberate the potential of carbon sources from feedstocks considered waste materials, i.e., \(\beta\)-D-rructofuranosidase (\(\beta\)-D-Fru), \(\beta\)-galactosidase (\(\beta\)-Gal), and glucoamylase (GLA). \(\beta\)-D-Fru is an enzyme that hydrolyses sucrose to glucose and fructose. This glyco- hydrolase can be found in plants, fungi, and bacteria cells, which are important elements of many regulatory and signalling pathways [16; 17; 18]. In industry, this enzyme is mainly produced by _Saccharomyces cerevisiae_ yeast. Invertex is an enzyme that has been used for years in various branches of the food industry, e.g., in the production of inverted sugar, artificial honey, alcoholic beverages, lactic acid, and glycerol. This enzyme has also been used in the pharmaceutical and cosmetic industries, and as an element of biosensors for sucrose detection [18]. The \(\beta\)-galactosidase of microbial origin is an enzyme that converts lactose into glucose and galactose.