Improved strategies to efficiently isolate thermophilic, thermotolerant, and heat-resistant fungi from compost and soil

Abstract

Thermophilic, thermotolerant and heat-resistant fungi developed different physiological traits, enabling them to sustain or even flourish under elevated temperatures, which are life-hostile for most other eukaryotes. With the growing demand of heat-stable molecules in biotechnology and industry, the awareness of heat-adapted fungi as a promising source of respective enzymes and biomolecules is still increasing. The aim of this study was to test two different strategies for the efficient isolation and identification of distinctly heat-adapted fungi from easily accessible substrates and locations. Eight compost piles and ten soil sites were sampled in combination with different culture-dependent approaches to describe suitable strategies for the isolation and selection of thermophilous fungi. Additionally, an approach with a heat-shock treatment, but without elevated temperature incubation led to the isolation of heat-resistant mesophilic species. The cultures were identified based on morphology, DNA barcodes, and microsatellite fingerprinting. In total, 191 obtained isolates were assigned to 31 fungal species, from which half are truly thermophilic or thermotolerant, while the other half are heat-resistant fungi. A numerous amount of heat-adapted fungi was isolated from both compost and soil samples, indicating the suitability of the used approaches and that the richness and availability of those organisms in such environments are substantially high.

Selection and identification of thermophilic yeast strains in leachate from the organic waste heap in Phu Luong district, Thai Nguyen province, Vietnam

“…due to low similarity with reference material (Table 4), which might, therefore, represent novel-undescribed species. Yeast is an important part of the microbiota observed during composting because of their ability to decompose dry recalcitrant acid and low-nitrogen-containing substrates in comparison to bacteria [3,5]. As many studies have shown the evolution of the fungal community in the process of composting, Saccharomycetales yeast is associated with the early stages of composting [4].…”

“…Yeast has a very important role in life and is present in the fermentation process of food processing [1]. In organic waste treatment, yeast has also been shown to play an important role in the fermentation process that breaks down organic waste [1,3]. Treatment of organic waste by microbial fermentation is a new technology with many outstanding advantages compared to other methods such as landfilling and incineration.…”

The Effect of Calcium Hydroxide on the Storage Behaviour of Poplar Wood Chips in Open-Air Piles

“…The isolated fungal species from poplar wood chips were classified as known thermophilic taxa, comprising members from Ascomycota, Mucoromycota and mycelia sterilia. The most abundant species, A. fumigatus, R. pusillus and T. lanuginosus, are ubiquitous and common species of thermophilic and thermotolerant fungi described in precedent studies in different wood chip types, diverse substrates (compost, mulch, soil) and different locations [14,34,[44][45][46]. In addition, most of the cultivated taxa are known to produce (ligno)cellulolytic enzymes, e.g.…”