# _Bacillus_ sp. GLN Laccase Characterization: Industry and Biotechnology Implications
## 4 Discussion
The significance of this group cannot be over-emphasized, as the members produce diverse and robust enzymes with promising candidacy in various sectors of the economy. However, some members of the _B. cereus_ group have also been reported to possess toxin-producing potential, posing both safety concerns and high risks in food processing and other production avenues [36]. Therefore, it is imperative to determine the generally recognized as safe (GRAS) status of the present isolate in the future study. This approach will determine if the wild isolate can either be improved through molecular optimization to produce the required enzyme or if recombinant DNA technology can harness the lacase production potential. Bacterial growth and enzyme production are markedly controlled by environmental conditions, suggesting that pH influences metabolic activities. The lacase production at a broad pH range by _Bacillus_ sp. GLN is attractive from an industrial perspective as most biomass suffer intermittent pH fluctuations due to the production/generation of variable compounds that overwhelm the standard buffering systems. Similar to the present finding, pH optimum at weakly acidic conditions of 5.0 has been reported to positively influence lacase production by _Bacillus_ sp. NU2 [37] and _Bacillus subtilis_[33]. However, lacases production by _Bacillus_ sp. BAB-4152 was negatively impacted at pH 5.0 but performed optimally at pH 8.0 [38]. Other credible reports have also demonstrated that some _Bacillus_ spp. optimally produced extracellular lacases within neutral conditions [39; 40]. Many factors, including the inductive effect of aromatic or phenolic compounds, strain preference, and metabolic capacities of the bacterial cells, greatly influence lacase production. _Bacillus_ sp. GLN displayed optimal lacase potential in the presence of ferulic acid and guaiacol. This finding indicated that the presence of these phenolic compounds upregulated the expression of lacase-encoding genes in strain GLN. Extracellular lactose production has been favorably promoted when the fermentation medium was adequately supplemented with ferulic acid [41; 42] or guaiacol [39; 43]. Supplementation of the production media with a nitrogen source is essential in bacterial growth and active lacase expression for lignolytic biomass modification [44]. The level of the influence of varying concentrations of nitrogen sources on bacterial lacase production has been attributed to the strain's peculiarity. Consequently, lacase secretion by different _Bacillus_ spp. was optimally supported by 3% peptome for _B. subtilis_ MTCC [45], 1% peptome for _Bacillus_ sp. AKRC01 [46], 0.1% tryptone for _Bacillus_ sp. [39], 0.1% yeast extract for _Bacillus amyldiefaciens_[30] ([PERSON] et al., 2020), and 0.5% peptome for _Bacillus aquimaris_ AKRC02 [47]. Meanwhile, lacase synthesis by another _Bacillus_ sp. strain was positively impacted by urea [48]. The amendment of the production medium with two nitrogen sources, yeast extract (0.15%) coupling tryptone (0.15%) and yeast extract (0.4%) coupling tryptone (0.2%), was reported to promote lactose production by _B. subtilis_ WPI [31] and _Bacillus marisflavi_ BB4 [49], respectively. However, the utilization of multiple nitrogen sources in the production system is unsustainable from an economic perspective. Similarly, carbon sources are essential for energy provision to facilitate microbial growth and metabolism. For this reason, optimizing the choice and concentration of carbon source for lactose production by _Bacillus_ sp. GLN was crucial to enhance its performance. The tested carbon sources favored lactose synthesis, with lactose at 0.5 g/L, causing the maximum enzyme yield from strain GLN. Likewise, another report indicated that lactose enhanced extracellular lactose synthesis from _Bacillus_ sp. [48]. Furthermore, lactose production by _Bacillus_ spp. has been promoted in the presence of other carbon source variants, including 3% sucrose [45], 1% dextrose [39], 10% glucose [18], and 0.2% galactose [49].