Levaduras cerveceras en biofertilizantes patagónicos

Abstract

The use of biofertilizers is a growing trend in agriculture when looking for environmentally friendly production practices. In El Bolsón (Patagonia, Argentina) such biofertilizers are produced in-farm using leaf-litter collected from native forests as source of mountain microorganisms. Here, we aimed to isolate and to identify yeasts associated with biofertilizers production. The leaf-litter was dominated by Lachancea nothofagi isolates with a few basidiomicetous species. In the next step, MMS, all isolates belonged to Saccharomyces eubayanus and S. uvarum; the samples presented a very distinctive cherry-chocolate aroma. The MMS was used to make a liquid biofertilizer (MML) which contained a more diverse community dominated by Picchia fermentans and P. membranifaciens. The MML could be applied directly to cultures or as complement with another derived biofertilizer named Bioestimulant (Bioest). The Bioest was clearly dominated by P. fermentans, but we also isolated Hanseniospora uvarum and a close relative to H. valbyensis. Saccharomyces eubayanus and S. uvarum were isolated with different frequency in MMS, MML and Bioest. Most of the yeast tested positive for the production of 3-indole-acetic acid (IAA) like compounds which are linked to the phytohormone family of auxins (therefore a desired feature in biofertilizers). The main producers were isolates identify as Candida boidinii from MML and Bioest; all P. fermentans isolates showed good production of IAA-like compounds. These two species are well known beer contaminants. The study showed the presence of many different brew-UHODWHG \HDVWVLQ3DWDJRQLDQ QDWXUDO HQYLURQPHQW (DFK ELRIHUWLOL]HU SURGXFWLRQ¶V step changed the yeast community and the yeast selected showed beneficial tray for plant production. Our study showed that brew-related yeasts, specially those considered as contaminant, could have good potential to be used as plant-growth promoters. These biofertilizers are under study for the application in hops (Nugget, Mapuche and Victoria) production in El Bolsón.