Examination and optimization of lignocellulolytic activity of S. gausapatum F28 on beechwood sawdust supplemented with molasses stillage

This study provides detailed analysis of the lignocellulolytic activity of a new isolate Stereum gausapatum F28, Serbian autochthonous fungi, on beechwood sawdust supplemented with cheap waste, sugar beet molasses stillage. Advanced multiple response optimization techniques were applied to improve ligninolytic and reduce hydrolytic activity as a requirement for potential biorefinery use. The applied techniques were supposed to select cultivation conditions that would give manganese peroxidase and laccase activities above 0.84 and 0.12 U g-1 substrate, respectively, and cellulase and xylanase activities below 1.12 and 1.4 U g-1 substrate. The optimal cultivation conditions that met the set requirements included molasses stillage concentration of 10 %, substrate moisture content of 53 %, incubation temperature of 23.5?C, and pH 5.2. The research showed that the addition of molasses stillage had positive effect on the enzyme production and that the optimal stillage concentration differed depending on the enzyme type (for laccase it was <5 %, manganese peroxidase ~12 %, cellulase ~21 %, xylanase ~16 %), which should be taken into consideration when optimizing the desired process.

A COMPARATIVE STUDY ON GROWTH AND LIGNOCELLULOLYTIC ACTIVITY OF NINE SARCODONTIA CROCEA STRAINS IN FOUR DIFFERENT MEDIA

The results of a study of growth characteristics, macromorphological features and biosynthetic potential of nine dikaryotic strains of Sarcodontia crocea (Polyporales, Basidiomycota) maintained in the Komarov Botanical Institute Basidiomycetes Culture Collection (LE-BIN) are presented. The strains studied were extracted from the basidiocarps collected on Malus domestica in the Belgorod, Oryol and Rostov Oblasts, as well as by seeding of basidiospores. The cultural and morphological characteristics and enzymatic activity of S. crocea were tested on both standard nutrient media (malt-extract agar – MEA, glucose-peptone agar – GPA) and modified semi-synthetic agarized media. Original compositions has been developed and for the first time nutrient media pre-pared using water-based wood extracts from Malus domestica (Malus-M) and Pyrus communis (Pyrus-M) have been approved. It was found that a significant reduction in growth rates was observed during the cultivation of S. crocea on agarized nutrient media of GPA, Malus-M and Pyrus-M. The studied strains on Malus-M and Pyrus-M exhibited high colony variability, sparse micelian mat, and loss of zonality and air mycelium intensity compared to MEA. It was shown that the composition of the nutrient medium strongly determined the ability of S. crocea strains to produce lignocelluolytic complex enzymes. The cellulolytic activity was noted for strains on all media studied, but no reliable differences were found in the cultivation of strains on sugar-rich MEA and three other semi-synthetic media. Only two strains (LE-BIN 2138 and 4355) were identified as having high cellulolytic activ-ity when grown on MEA. The absence of lignolytic complex enzyme activity was demonstrated when the strains were cultivated on new modified semi-synthetic agarized media of Malus-M and Pyrus-M.

The genome sequence of the soft-rot fungus Penicillium purpurogenum reveals a high gene dosage for lignocellulolytic enzymes

The high lignocellulolytic activity displayed by the soft-rot fungus P. purpurogenum has made it a target for the study of novel lignocellulolytic enzymes. We have obtained a reference genome of 36.2Mb of non-redundant sequence (11,057 protein-coding genes). The 49 largest scaffolds cover 90% of the assembly, and CEGMA analysis reveals that our assembly covers most if not all all protein-coding genes. RNASeq was performed and 93.1% of the reads aligned within the assembled genome. These data, plus the independent sequencing of a set of genes of lignocellulose-degrading enzymes, validate the quality of the genome sequence. P. purpurogenum shows a higher number of proteins with CAZy motifs, transcription factors and transporters as compared to other sequenced Penicillia. These results demonstrate the great potential for lignocellulolytic activity of this fungus and the possible use of its enzymes in related industrial applications.

Isolation of Fungi and Bacteria Associated with the Guts of Tropical Wood-Feeding Coleoptera and Determination of Their Lignocellulolytic Activities

The guts of beetle larvae constitute a complex system where relationships among fungi, bacteria, and the insect host occur. In this study, we collected larvae of five families of wood-feeding Coleoptera in tropical forests of Costa Rica, isolated fungi and bacteria from their intestinal tracts, and determined the presence of five different pathways for lignocellulolytic activity. The fungal isolates were assigned to three phyla, 16 orders, 24 families, and 40 genera;Trichodermawas the most abundant genus, detected in all insect families and at all sites. The bacterial isolates were assigned to five phyla, 13 orders, 22 families, and 35 genera;Bacillus,Serratia,andPseudomonaswere the dominant genera, present in all the Coleopteran families. Positive results for activities related to degradation of wood components were determined in 65% and 48% of the fungal and bacterial genera, respectively. Our results showed that both the fungal and bacterial populations were highly diverse in terms of number of species and their phylogenetic composition, although the structure of the microbial communities varied with insect host family and the surrounding environment. The recurrent identification of some lignocellulolytic-positive inhabitants suggests that particular microbial groups play important roles in providing nutritional needs for the Coleopteran host.

Characterisation and effects of a xylanase enzyme preparation extracted from Thermomyces lanuginosus cultures

This paper describes the production of an enzyme preparation from the fungus Thermomyces lanuginosus. Thermal resistance, pH stability and lignocellulolytic activity of the enzyme preparation high in xylanase were studied on a variety of grains and forages. The enzyme preparation preserved more than 70% of its original xylanase activity for 4 and 1 h at 60 and 70 °C, respectively. The xylanase activity remained over 80% when the preparation was incubated for 30 min at pH 4.5. In vitro digestibility studies indicated that the enzyme digested 7.5, 8.5 and 8.0% of the dry matter (DM) of barley meal, wheat bran and oat meal samples, respectively. When applying 60-min incubation, 7.5, 7.3 and 8.4% of DM of the oat straw, alfalfa hay and triticale straw was digested, respectively. When the time of digestion was increased to 360 min, the sunflower hull showed 15.8% DM digestibility.