## 3 Results and Discussion
### Optical Microscopy Observations
In conclusion, the production as reflected in the activity of enzymes from _T. atroviride_ was cyclic, the highest level being at 12 days of incubation for the control. Irradiation of _T. atroviride_ with a blue-light 400 nm laser was found to influence the protease and cellulase activities. The highest positive impact of the laser on the protease activity compared to the control was observed after 5 days of incubation from the first 60 s irradiation. The highest negative impact of the laser on the protease activity compared to the control was observed after 15 days of incubation and 3 \(\times\) 300 s irradiations during this period. The highest positive impact of the laser on the cellulase activity compared to the control was observed after 15 days of incubation and 3 \(\times\) 60 s irradiations during this period. The highest negative impact of the laser on the cellulase activity compared to the control was observed after 12 days of incubation and 3 \(\times\) 300 s irradiations during this period, but the 3 \(\times\) 60 s irradiation had a similar negative impact. The effects seem to exhibit a hormesis behavior. The irradiation for 3 \(\times\) 300 s induces an intensification in the UV absorption of the supernatant, reflecting a higher concentration of UV-absorbing compounds. Regarding the morphological analysis of the _T. atroviride_ strain, there is an increase in the number and dimensions of conidia as a response to irradiation, and there also seems to be an effect on the chlamdospore formation. This was the first study to report blue laser-induced effects on cellulase and protease activities and on conidia dimensions of _Trichoderma_. More in-depth investigations are needed to optimize the system and technology for possible applications in industry and agriculture. Figure 7: Abundance of conidia: (**a**) conidia of non-irradiated _T. atroviride_; (**b**) conidia of 3 \(\times\) 60 s irradiated _T. atroviride_; (**c**) conidia of 3 \(\times\) 300 s irradiated _T. atroviride_; (**d**) average number of conidia/mL in the irradiated and non-irradiated _T. atroviride_, as measured using hemocytometer. The columns with the same letter do not differ significantly. Bars are \(\pm\)error bars, \(\alpha\) = 0.05, \(n\) = 3; (**e**) average diameter of conidia The columns with the same letter do not differ significantly. Bars are \(\pm\)error bars, \(\alpha\) = 0.05, \(n\) = 15. White labelled bars represent dimension at microscopic level—50 \(\upmu\)m.  
**Author Contributions:** Conceptualization, D.C.-A. and F.O. ; methodology, F.O., A.A.E. and B.T. ; validation, I.-A.B. and N.T. ; formal analysis, I.-A.B., N.T., A.A.E. and B.T. ; investigation, I.-A.B., N.T., A.A.E. and B.T. ; resources, F.O. and A.A.E. ; data curation, I.-A.B. and N.T. ; writing--original draft preparation, I.-A.B. and N.T. ; writing--review and editing, D.C.-A. and F.O. ; visualization, D.C.-A. and F.O. ; supervision, D.C.-A. and F.O. ; project administration, D.C.-A. and A.A.E. ; funding acquisition, F.O. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by project POC-A1-A1.2.3-G-2015-P_40_352-SECVENT, Sequential processes to close bioeconomy side stream and innovative bioproducts resulted from these, contract 81/2016, SMIS 105684, funded by Cohesion Funds of the European Union, subsidiary project 1477/2020 TrichoSpor. The APC was funded by the same project. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Data are available from authors. **Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. Figure 8: The conidia of _T.