Ethanol Production from Cellulose by Two Lignocellulolytic Soil Fungi

Abstract

The present work examines the production of ethanol via direct fermentation of pure celluloses and lignocellulosic wastes by two soil fungi isolated under anaerobic conditions. The strains were cultured on a defined medium containing filter paper slurry as the carbon source under anaerobic, microaerophilic, and aerobic conditions. After complete degradation of the cellulose, lignocellulases and fermentation products were determined. Highest activities for Trichocladium canadense (strain QI0) and the basidiomycete strain (strain H2), were obtained when cultures were incubated under microaerophilic conditions and air, respectively. Laccase activity was present in the culture supernatants of both strains, but peroxidase was only produced by strain H2. Ethanol was the major nongaseous fermentation product. Highest conversion of available cellulose to ethanol was obtained with strain QI0 (90-96%), under microaerophilic conditions. Ethanol production decreased when microcrystalline cellulose and lignocellulosic substrates were used.

Identification of Cellulose-Responsive Bacterial and Fungal Communities in Geographically and Edaphically Different Soils by Using Stable Isotope Probing

“…It is known for its celluloytic activity; when grown under microaerophilic conditions, certain Trichocladium species can convert ca. 90 to 96% of available cellulose to ethanol (15). Members of the genus Chaetomium are known to degrade lignocellulosic biomass and various carbohydrates (55).…”

Degradation of lignosulfonic and tannic acids by ligninolytic soil fungi cultivated under icroaerobic conditions

“…However, these results were lower than results confirmed in the present study. The microaerobic fungi Trihcocladium canadense and H2 were also able to grow in LA and produce laccase and other peroxidases (Durrant, 1996). Fungi may produce different enzymes depending on genetic characteristics or environment conditions (Eggen, 1999),.…”

“…Non-basidiomycete fungi are also good degraders of wood, producing nonspecific extracellular ligninolytic enzymes such as manganese peroxidase and laccase, when grown in media containing lignin-related compounds. Most fungi need oxygen, at least in small amounts in order to grow; however, some anaerobic phycomycetous fungi capable of degrading lignocellulosic materials are present in the rumen microbiota (Durrant, 1996). Tolerance for low levels of oxygen has also been observed in some aquatic fungi, yeasts and several filamentous fungi such as Fusarium oxysporum, Mucor hiemalis, Aspergillus fumigatus which can fermentate sugars (Singh et al, 1992).…”

“…The aim of this work was to study the ability of soil fungi to degrade lignosulfonic and tannic acids and produce ligninolytic enzymes under microaerobic conditions. (Durrant, 1996) were used in this work. Cultures were cultivated in 0.2% lignosulfonic acid (LA) or tannic acids (TA) as sole carbon sources in a defined liquid medium containing per liter: KH 2 PO 4 (1 g); (NH 4 ) 2 HPO 4 (0.5 g); CaCl 2 (0.3 g); L-cysteine chloridrate as reducing oxygen agent (1 g); resazurine 0.1% as reduction indicator dye (1 ml); micronutrients solution (1 ml); vitamins solution (0.5 ml), pH 5.5-6.0.…”