## 3 Results  
### Inhibition Assays  
Pseudomonas sp., strain L5B5, was selected within a set of airborne mine bacteria after a first pathogenic bacterial and fungal inhibition assays. Strain L5B5 was able to prevent the growth of _Bacillus cereus_ and _Staphylococcus aureus_, as well as the inhibition of all the fungal strains used in the test. A second assay for pathogenic bacteria inhibition using glycerol as main source of carbon resulted in a progressive inhibition of pathogens depending on the filtrate concentration. Thus, the crude filtrate had no effect or slight bacteriostatic influence on pathogenic bacteria. The concentrated filtrate 2X inhibited _B. cereus_, whereas the 5X filtrate inhibited _B. cereus_, _S. aureus_, and _A. baumannni_ (Figure 1).  
Likewise, results in a second assay using filtrates after culturing strain L5B5 with NB and glucose, mannose, and fructose showed a similar behavior than when cultured with glycerol (Figure 2). That is, a bacteriostatic effect prevailed either with glycerol or alternative source carbons used for the culture of strain L5B5, being especially successful in delaying the exponential phase in _B. cereus_ and _S. aureus_ and limiting the duration of this phase significantly.  
Figure 1: Second inhibition assay of pathogens by _Pseudomonas_ sp., strain L5B5, filtrates after culturing with glycerol as main source of carbon. Positive control: Aeruginosa-Gly is _Pseudomonas aeruginosa_ in NB-Glycerol; Aureus-Gly is _Staphylococcus aureus_ in NB-Glycerol; Baumannni-Gly is _Acinetobacter baumannni_ in NB-Glycerol; Cereus-Gly is _Bacillus cereus_ in NB-Glycerol; Coli-Gly is _Escherichia coli_ in NB-Glycerol. Inhibition test: L5B5-Gly is crude filtrate of strain L5B5 culture with NB-Glycerol; L5B5-Gly is 2X concentrated filtrate of strain L5B5 with NB-Glycerol; L5B5-Gly-5X is 5X concentrated filtrate of strain L5B5 with NB-Glycerol.  
A fungal inhibition assay showed the capability of strain L5B5 to inhibit completely the fungal growth of _Aspergillus versicolor_, _Penicillium chrysogenum_, _Cidosporium cladosporioides_, and _Ochroconis lascauxensis_, whereas in the case of _Fusarium solani_ the limitation of growth was relevant (Figure 3A), especially when comparing with the positive control (Figure 3B), where an environmental _Streptomyces_ sp. was used to check the growth of fungi with a non-antiungal producer bacterium.  
Figure 3: _Pseudomonas_ sp., strain L5B5, fungal inhibition of growth assay **(A)**, in comparison with positive control using an environmental bacterium without antifungals production (**B**) and normal fungal growth in NA-Glycerol plates (**C**).  
Figure 2: Second assay of inhibition of pathogens by _Pseudomonas_ sp., strain L5B5, filtrate using alternative source carbons, NB-Glucose (**left**), NB-Mannose (**center**) and NB-Fructose (**right**). Positive controls representing the normal growth of pathogens without the filtrates of _Pseudomonas_ sp., strain L5B5 are also displayed in graphics, with the name of the tested species (Aeruginosa, Aureus, Baumanni, Cereus and Coli) and the used carbon sources (Glu-Man-Fru). Inhibition test: Crude filtrates of strain L5B5 culture with NB-Glucose-bacteria are represented as L5B5-Glu-(Aeruginosa, Aureus, Baumanni, Cereus or Coli) (**left**), NB-Mannose-bacteria as L5B5-Mn-(Aeruginosa, Aureus, Baumanni, Cereus or Coli) (**center**), NB-Fructose-bacteria as L5B5-Fru-(Aeruginosa, Aureus, Baumanni, Cereus or Coli) (**right**).