No abstract

Bioabatement is a potential method to remove inhibitory compounds from lignocellulose hydrolysates that could be incorporated into a scheme for fermentation of ethanol from cellulose. Coniochaeta ligniaria NRRL30616, an Ascomycete that metabolizes furfural and 5-hydroxymethylfurfural, is a unique strain that may be useful for detoxifying biomass sugars. NRRL30616 and 23 related fungal strains were screened for the ability to metabolize furans and grow in dilute-acid hydrolysate of corn stover. NRRL30616 was the best strain for removal of inhibitors from hydrolysate, and abatement of hydrolysate by inoculation with the strain allowed subsequent yeast fermentation of cellulose to ethanol.

Bioabatement is a potential method to remove inhibitory compounds from lignocellulose hydrolysates that could be incorporated into a scheme for fermentation of ethanol from cellulose. Coniochaeta ligniaria NRRL30616, an Ascomycete that metabolizes furfural and 5-hydroxymethylfurfural, is a unique strain that may be useful for detoxifying biomass sugars. NRRL30616 and 23 related fungal strains were screened for the ability to metabolize furans and grow in dilute-acid hydrolysate of corn stover. NRRL30616 was the best strain for removal of inhibitors from hydrolysate, and abatement of hydrolysate by inoculation with the strain allowed subsequent yeast fermentation of cellulose to ethanol.

Coniochaeta ligniaria NRRL30616 is an ascomycete that grows with yeast-like appearance in liquid culture. The strain has potential utility for conversion of fibrous biomass to fuels or chemicals. Furans and other inhibitory compounds in lignocellulosic biomass are metabolized by NRRL30616, facilitating subsequent microbial fermentation of biomass sugars. This study undertook initial characterization of the genetic system of C. ligniaria NRRL30616. Transformation using hygromycin as a dominant selectable marker was achieved using protoplasts generated by incubating cells in 1% (v/v) β-mercaptoethanol, followed by cell wall-digesting enzymes. Thirteen chromosomes with an estimated total size of 30.1 Mb were detected in C. ligniaria. The GC content of chromosomal DNA and of coding regions from cDNA sequences were 49.2 and 51.9%, respectively. This study is the first report of genome size, electrophoretic karyotype, and transformation system for a member of the Coniochaetales.

Nowadays, the discovery of lignocellulolytic microorganisms that are better adapted to operational conditions while exhibiting the strong degrading activities is highly desired for successful lignocellulose biotransformation processes. In this study, microorganisms were isolated from lignocellulose-rich composting materials by selective methods. A screening of isolates known to have lignocellulolytic abilities was performed using several tests. Seven microorganisms showed ligninolytic potential and were subjected for further analysis according to their degrading activity. The fungus Pseudallescheriaangusta MF4 demonstrated high decolorization rates for three aromatic dyes: Poly R-478, Poly S-119, and Remazol Brilliant Blue R. In addition, the fungus showed a high production rate of ligninolytic enzymes in the presence of inducers. This fungus achieved the highest values of growth after 21 days of incubation on sawdust without any additional nutrients. Owing to its proven ligninolytic activity and capability of growing on a lignocellulosic substrate, the application of this isolate could be of interest in different biotechnological applications, particularly in biological treatment of wood fibres in order to improve the production of wood-based composites.