# Evaluating Soil Bacteria for the Development of New Biopreparations with Agricultural Applications
## 4 Discussion
Interestingly, none of the samples of post-harvest residues inoculated with strains WK-7 and WK-8 exhibited the release of total reducing sugars (TRS). This might be due to the low levels of enzyme secretion, low or inhibited enzyme activity, or the uptake of already released sugars for cell metabolism. Oligo- and monosaccharides, especially glucose, play crucial roles in cell development and growth, acting as energy carriers, gene expression regulators, building blocks for cell components, and moieties for the synthesis of crucial metabolites [54]. The soil bacteria _Bacillus_ sp. P3 has been found to have biodegradation potential against several different types of lignocellulosic biomass. The maximal reducing sugar release was noticed after 20 days of incubation (55.5 mg/g), with a slight decrease between days 5 (50.2 mg/g) and 10 (41.2 mg/g). This indicates fluctuation of TRS content, probably due to microbial metabolism [55]. Strains of _B. velezensis_ UPF-B1 and UPF-B2 have been reported to biodegradable tritcale and sugarcane bagasse. The highest-reducing sugar concentrations were reached after 5 days (120 h), with around 18 mg/mL, for both strains grown on mixed substrate at pH 5.5 and pH 7.0 [41]. The marine strains _Bacillus safensis_ NIORKK2 (cellulase) and _Bacillus_ sp. NIORKKK7 (xylanase) have been shown to have biodegradation potential against various biomasses, including rice bran, wheat bran, rice, wheat hay, and maize cobs, as well as mango and bamboo leaves. The maximal reducing sugar concentrations ranged from 56.94 mg/g to 206.21 mg/g for cellulolytic enzymes and 53.91 mg/g to 178.87 mg/g for xylanolytic enzymes with untreated substrates [38]. Prior pretreatment of the substrates led to increases in the release of reducing sugars. Applying a cocktail of both enzymes resulted in further increases in saccharification effectiveness, suggesting that cellulolytic and xylanolytic enzymes have a synergistic effect on lignocellulosic biomass degradation [38]. The amounts of TRS released from the substrates after 5-day incubation differed significantly. The highest concentrations of TRS were observed for strain WK-14 with winter barley (22.07 mg/mL) and tritticale (18.10 mg/mL). However, mulching is considered the only feasible agotechnical pretreatment method for in situ biodegradation of post-harvest residues. On-field conditions are also far from optimal for strain growth and biodegradation, due to fluctuating conditions of temperature, oxygenation, and humidity, as well as the presence of natural competitors. Enzymes play a crucial role in the decomposition of plant residues [23; 56]. The addition of the tested microorganisms is expected to enhance the microbial decomposition of residues. Other researchers have demonstrated the ability of certain microbial strains to decompose various crop residues. For instance, [PERSON] et al. (2016) found that _B. subtilis_ IMB B-7516 and _B. licheniformis_ IMB B-7515 strains exhibited the ability to decompose a range of crop residues, achieving a decomposition rate of 40-60% under laboratory conditions [57]. In a recent study by [PERSON] et al. (2022) [58], the use of multi-enzyme producing _Bacillus_ sp. was shown to be an effective and eco-friendly method for the biodegradation of organic waste, with synergistic effects. This approach has potential benefits for commercial enzyme production and biotechnological applications. The synergistic effects of strains may also explain why the mixture of microorganisms used in this study resulted in the fastest decomposition of residues. The availability of phosphorus, a crucial nutrient for plant growth and development, is often limited by its occurrence in insoluble forms in soil. Phosphate-solubilizing microorganisms (PSMs) have been shown to convert these insoluble phosphates into plant-available forms, enhancing plant growth and reducing dependence on inorganic fertilizers [59; 60]. Various PSMs, including bacteria and fungi, have been identified as being capable of effectively solubilizing phosphorus [61; 62; 63].