# _Bacillus_ sp. GLN Laccase Characterization: Industry and Biotechnology Implications
## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Bacterial Source** &
\begin{tabular}{c} **Optimal Prod.** \\ **Time (h)** \\ \end{tabular} & **Assay Substrate** & **Optimal pH** & **Optimal Temp.** & **Half-Life of GLN** & **Activity Enhancing** & **References** \\ \hline _Bacillus sp. GLN_ & 48 & ABTS & 9 & 90 & \textgreater{}270 min at 100 \({}^{\circ}\)C & Cu2\({}^{\circ}\) & This study \\ _Gebacillus haemorrhings_ MH600 & 72 & Guaticol & 5 & 90 & - & Cu2\({}^{\circ}\), Cu2\({}^{\circ}\), Cd2\({}^{\circ}\), Li\({}^{\circ}\) & [18] \\ _Bacillus populations_ SVA & 96 & ABTS & 5.5 & 85 & 1 h at 55 \({}^{\circ}\)C & Cu2\({}^{\circ}\), Cd2\({}^{\circ}\) & [10] \\ _Lymphiculus fasiformis_ & - & DMP & 10.4 & 70 & 15.9 h at 60 \({}^{\circ}\)C & Cu2\({}^{\circ}\) & [59] \\ _Bacillus_ sp. PC-3 & 36 & ABTS & 7 & 60 & 3.75 h at 60 \({}^{\circ}\)C & - & [11] \\ _Bacillus subtilis_ & - & ABTS & 3 & 75 & 2 h at 80 \({}^{\circ}\)C & - & [60] \\ _Gebacillus fasromiculus fMS5_ & 96 & ABTS & 4+5 & 55-60 & - & - & [61] \\ _Gebacillus sp. Tumlänensis_ & - & ABTS & 5 & 60 & - & Cu2\({}^{\circ}\) & [16] \\ _Gebacillus_ sp. ID2\({}^{\circ}\) & - & Springaldazine & 7 & 55 & 30 min at 60 \({}^{\circ}\)C & Cu2\({}^{\circ}\) & [17] \\ _Bacillus_ sp. ENT & - & Springaldazine & 6 & 70 & \textgreater{}2 h at 60 \({}^{\circ}\)C & - & [62] \\ _Catenivalous japonicus_ & - & DMP & 9.2 & 70 & 60 min at 90 \({}^{\circ}\)C & - & [63] \\ _Anonymous glycans_ SK3-4 & - & Springaldazine & 7 & 75 & 155 min at 65 \({}^{\circ}\)C & Cu2\({}^{\circ}\), Mg2\({}^{\circ}\) & [64] \\ _Thrombyla fisica_ & 36 & DMP & 8 & 60 & \textgreater{}3 h at 50 \({}^{\circ}\)C & - & [65] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of the biochemical characteristics of GLN license with other reported bacterial accesses. The GLN laccase showed an excellent stability profile in the presence of the various metal ions examined. Biocatalytic enhancement was demonstrated in the presence of Cu\({}^{2+}\), suggesting the role of this ion in the maintenance of active catalytic orientation of the lacase during enzyme reaction. A study on the formulation of functionalized copper oxide-lactamase nanoparticles demonstrated that the nanoreactor exhibited excellent catalysis with a high turnover number compared to the free lactose [70]. Further, a probe into the cause via mass spectrometry showed that copper ions were lost during the reaction cycle of the free lacase. At the same time, the CuO nanoparticles acted as a source of copper ions for the lacase nanoreactor, thereby sustaining the enzyme structure and catalytic performance [70]. This report further sheds light on the performance enhancement demonstrated by lacases in the presence of Cu\({}^{2+}\), as documented elsewhere [7; 10; 71]. The GLN lacase stability pattern against the tested metal ions is superior to the report of [PERSON] and co-workers on lacase from _B. marisflavi_ BB4 [49]. Conversely, lacase from _B. cereus_ UV25 was strongly inhibited by Fe\({}^{2+}\) (28.16%), K\({}^{+}\) (30.60%), and Zn\({}^{2+}\) (53.49%) compared to GLN lacase, while Ca\({}^{2+}\), Cu\({}^{2+}\), Mg\({}^{2+}\), and Mn\({}^{2+}\) greatly promoted the enzyme activity [68]. The stability of GLN lacase in the presence of tested metal ions underpinned its potential application in industrial effluent treatment.