Genome sequencing and functional characterization of a Dictyopanus pusillus fungal enzymatic extract offers a promising alternative for lignocellulose pretreatment of oil palm residues.

The pretreatment of biomass remains a critical requirement for bio-renewable fuel production from lignocellulose. Although current processes primarily involve chemical and physical approaches, the biological breakdown of lignin using enzymes and microorganisms is quickly becoming an interesting eco-friendly alternative to classical processes. As a result, bioprospection of wild fungi from naturally occurring lignin-rich sources remains a suitable method to uncover and isolate new species exhibiting ligninolytic activity. In this study, wild species of white rot fungi were collected from Colombian forests based on their natural wood decay ability and high capacity to secrete oxidoreductases with high affinity for phenolic polymers such as lignin. Based on high activity obtained from solid-state fermentation using a lignocellulose source from oil palm as matrix, we describe the isolation and whole-genome sequencing of Dictyopanus pusillus, a wild basidiomycete fungus exhibiting ABTS oxidation as an indication of laccase activity. Functional characterization of a crude enzymatic extract identified laccase activity as the main enzymatic contributor to fungal extracts, an observation supported by the identification of 13 putative genes encoding for homologous laccases in the genome. To the best of our knowledge, this represents the first report of an enzymatic extract exhibiting laccase activity in the Dictyopanus genera, offering means to exploit this species and its enzymes for the delignification process of lignocellulosic by-products from oil palm.

Activity of Bacillus thuringiensis hybrid protein against a lepidopteran and a coleopteran pest.

The use of Cry proteins from Bacillus thuringiensis are an important strategy for biological control. Recently it has been demonstrated that Cry hybrid proteins (by domain swapping) resulted in improved toxicities in comparison with parental proteins. Here, an SN1917 hybrid toxin was constructed and tested against Colombian pest insects Tecia solanivora (Lepidoptera: Gelechiidae), a severe potato pest, and Hypothenemus hampei (Coleoptera: Scolytidae), which attacks coffee crops. The SN1917 protoxin had a concentration causing 50% mortality (LC(50)) of 392 ng cm(-2), and SN1917 toxin showed an LC(50) of 201 ng cm(-2) against T. solanivora first instar larvae. The two parental toxins (Cry1B and Cry1I) used to make this new hybrid protein caused a mortality of 60% and 52%, respectively. Unfortunately, H. hampei first instar larvae proved to be resistant to the toxin. We conclude that SN1917 is an option for biological control and resistance management of T. solanivora. Implications for H. hampei are discussed.

Producción de fructooligosacaridos (FOS) por tecnología de enzimas. Parte I: Evaluación de aislados nativos de hongos para la producción de FOS / Production of fructooligosaccharides (FOS) by enzymatic technology. Part I: Evaluation of native isolates obtained from fungi for production of FOS

En este trabajo se estudió la influencia de la concentración de sacarosa, extracto de levadura y carbonato de calcio en la producción de FOS y la actividad fructosiltransferasa (FTF) en fermentaciones de 24, 36 y 48 horas usando Aspergillus niger AN166 como modelo biológico. La actividad FTF más alta de A. niger fue obtenida con 20 por ciento de sacarosa y 0.2 por ciento de extracto de levadura. El carbonato de calcio no tiene un efecto significativo en la producción de FOS. Adicionalmente, el medio de cultivo derivado del trabajo anterior fue usado para el aislamiento de hongos nativos de diferentes regiones de Cundinamarca (Colombia). Los aislados fueron evaluados con relación a la producción de FOS y actividad FTF. Solamente cinco aislados mostraron una mayor producción de FOS y actividad FTF que el A. niger AN166

Producción y caracterización de extractos enzimáticos crudos con actividad de fructosiltransferasa / Production and characterization of crude extracts with fructosyltranferase activity

Se encontró que extractos crudos provenientes del cultivo de Aspergillus niger cepa AN 166 poseen alta actividad de fructosiltransferasa. Se implementó un ensayo enzimático para evaluar las actividades de hidrolisis y transferencia observadas para la enzima que produce este microorganismo. Fueron encontradas actividades hidrolítica y de transferencia intra y extracelulares. Se encontro una mayor actividad extracelular de transferencia que la correspondiente encontrada para la fracción intracelular. La caracterización realizada permitirá posteriores estudios a nivel molecular de la o las enzimas que presentaron la actividad evaluada en esta cepa