Potential impacts of seasonal and altitudinal changes on enzymatic peat decomposition in the High Andean Paramo region of Ecuador.

The Andean Paramo is a vast ecosystem, characterized by distinct vegetational zones at several altitudinal levels with huge water storage and carbon fixation capacity within its peat-like andosols, due to a slow decomposition rate of organic matter. These characteristics become mutually related as enzymatic activities increase with temperature and are associated with oxygen penetration, restricting the activity of many hydrolytic enzymes according to the enzyme Latch Theory. This study describes the changing activity of sulfatase (Sulf), phosphatase (Phos), n-acetyl-glucosaminidase (N-Ac), cellobiohydrolase (Cellobio), ß-glucosidase (ß-Glu), and peroxidase (POX) on an altitudinal scale from 3600 to 4200 m, in rainy and dry seasons at 10 and 30 cm sampling depth, related to physical and chemical soil characteristics, like metals and organic elements. Linear fixed-effect models were established to analyze these environmental factors to determine distinct decomposition patterns. The data suggests a strong tendency towards decreasing enzyme activities at higher altitudes and in the dry season up to two-fold stronger activation for Sulf, Phos, Cellobio, and ß-Glu. Especially the lowest altitude showed considerably stronger activity of N-Ac, ß-Glu, and POX. Although sampling depth revealed significant differences for all hydrolases but Cellobio, it had minor effects on model outcomes. Further organic rather than physical or metal components of the soil explain the enzyme activity variations. Although the levels of phenols coincided mostly with the soil organic carbon content, there was no direct relation between hydrolases, POX activity, and phenolic substances. The outcome suggests that slight environmental changes with global warming might cause important changes in enzyme activities leading to increased organic matter decomposition at the borderline between the paramo region and downslope ecosystems. Expected extremer dry seasons could cause critical changes as aeration increases peat decomposition leading to a constant liberation of carbon stocks, which puts the paramo region and its ecosystem services in great danger.

Prospection of Psychrotrophic Filamentous Fungi Isolated from the High Andean Paramo Region of Northern Ecuador: Enzymatic Activity and Molecular Identification.

The isolation of filamentous fungal strains from remote habitats with extreme climatic conditions has led to the discovery of a series of enzymes with attractive properties that can be useful in various industrial applications. Among these, cold-adapted enzymes from fungi with psychrotrophic lifestyles are valuable agents in industrial processes aiming towards energy reduction. Out of eight strains isolated from soil of the paramo highlands of Ecuador, three were selected for further experimentation and identified as Cladosporium michoacanense, Cladosporium sp. (cladosporioides complex), and Didymella sp., this last being reported for the first time in this area. The secretion of seven enzymes, namely, endoglucanase, exoglucanase, ß-D-glucosidase, endo-1,4-ß-xylanase, ß-D-xylosidase, acid, and alkaline phosphatases, were analyzed under agitation and static conditions optimized for the growth period and incubation temperature. Cladosporium strains under agitation as well as incubation for 72 h mostly showed the substantial activation for endoglucanase reaching up to 4563 mU/mL and xylanase up to 3036 mU/mL. Meanwhile, other enzymatic levels varied enormously depending on growth and temperature. Didymella sp. showed the most robust activation at 8 °C for endoglucanase, ß-D-glucosidase, and xylanase, indicating an interesting profile for applications such as bioremediation and wastewater treatment processes under cold climatic conditions.