# Unveiling Biological Activities of Marine Fungi: The Effect of Sea Salt
## 4 Discussion  
Metabolites from marine fungi are diverse and are described as expressing various biotechnological relevant activities. Our results confirm this with an emphasis on enzymatic, antibacterial, anti-yeast and antioxidant activities, revealing significant bioresources for outstanding opportunities to study natural product drug discovery. Fungi express a spectrum of enzymes crucial for host colonization [48] and for the degradation of organic matter to obtain nutrients [34]. A wide range of activities have been identified from marine fungi, including antibacterial, antidiabetic, antifungal, antitumor, and cytotoxic activities, many of which can be attributed to specific enzymes [10]. Eighty-eight percent of the strains we assayed express cellulolytic activity, 68% express xylanases, and 92% and 80% express pectinases and pectin lysates, respectively. Xylanas are glycoside hydrolases able to catalyze the hydrolysis of xylan (one of the most abundant polysaccharides in plants and algae) to xylose [49]. The most well-known examples of fungal species expressing xylanas belong to the genera _Aspergillus_, _Penicillium_ and _Trichoderma_, these being the main commercial source of this type of enzyme [49]. Here, we demonstrate that _A. affinis_, _A. protuberus_, _Pen. lusitanum_, and _T. aestarium_ are also able of produce xylanas. These enzymes can be used in the pulp and paper industry, as a food supplement to poultry, in bread and various drinks, in textiles, in bleaching processes, and in the production of other industrial reagents [50]. [PERSON] et al. [51] described a group of marine fungi--commonly occurring in mangroves expressing xylanase and cellulase activities. Additionally, [PERSON] et al. [52] showed that _Lophiostoma mangrovei_ and _Hypoxylon oceanicum_ can produce hemicellulases such as xylanas. Our strains of _Neocamarosporum_, a typical genus found in association with halophytes (salt tolerant plants) in marine and estuarine habitats, also showed xylanolytic activity. Other lignicolous fungi isolated from submerged wood such as _Remispora submersa_, _Z. maritima_, _Z. pseudomaritima_, _S. taivanensis_, _Paralulworthia hulina_, and _Lulworthia_ cf. _purpurea_ also showed cellulolytic activity. Lignicolous mangrove fungi such as _Halorosellinia oceanica_, _Lignincola laevis_, and _Trematosphaeria mangrovei_ are capable of producing extracellular cellulases, namely endoglucanase, cellobiohydrolase, and \(\beta\)-glucosidase [53]. Previous studies have shown that marine fungi are also capable of expressing amylases [54; 55]. Seventeen (out of 25) strains expressed amylolytic activity. This group of enzymes can catalyze the hydrolysis of starch molecules and have many industrial applications, such as in detergent and fuel alcohol production, in textiles, in the paper industry, and in bakeries [49; 56]. Some genera including some marine ones are reported as a source of amylases, such as _Alternaria_, _Aspergillus_, _Ceriospropesis_, _Coriospora_, _Dendryphiella_, _Lindra_, _Lulworthia_, _Microtthia_, _Penicillium_, _Trichoderma_, and _Zalerion_[57]. Urea represents one of the sources of nitrogen that support growth in marine fungi [58]. Metalloenzymes such as urease catalyze the hydrolysis of urea to carbon dioxide and ammonia [59]. Ureolytic microorganisms are able to precipitate carbonates and could be used for biorecovery of valuable metals disseminated in the environment [60]. From the strains assayed, 44% have ureolytic activity (_A. protuberus_, _R. submersa_, _Nederviesia aestuarina_, _Neptunomyces aureus_, and _S. taivanensis_). Chitinolytic activity was detected in _A. affinis_, _A. protuberus_, _C. rubrum_, _E. cladophone_, _R. submersa_, _Neo. aestuarina_, _Nep. aureus_, _Para. fusiforme_, _Pen. lusitanum_, _T. aestuarium_, and _Verrucoconidhyrium ambiguum_. Chitin is a biopolymer of N-acetylglucosamine and is a structural component of fungal cell walls, as well as of the exoskeletons of several marine invertebrates, and can be degraded by chitinase into monomers [49].