Characterization of auxiliary enzymes (REDOX) from the termite Coptotermes gestroi that cooperate with glycolytic hydrolases

Author(s)

Robson Tramontina

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2016-08-07

Examining board members

Fabio Marcio Squina; Valdeir Arantes; Juliana Velasco de Castro Oliveira; Roberto Ruller

• Advisor: Fabio Marcio Squina

Abstract

Discovering novel enzymes sources for lignocellulose degradation and detoxification into fermentable sugars is considered one of the biggest bottlenecks towards the sustainable production of second-generation ethanol. In nature, termites are biological models for plant biomass conversion. Accordingly, the termite Coptotermes gestroi degrades hardwoods to harness their nutrients, through a complex symbiosis between the host termite and prokaryotic and eukaryotic symbionts. A deep insight into the unknown termite biology was obtained by applying "omics" technologies, especially with respect to holobiontic, biochemical and physiological aspects applied to its diet. Many hypotheses about a class of endogenous proteins ¿ the so called pro-oxidant antioxidant and detoxifying enzymes (PADs) and auxiliary enzymes (AAs) ¿ indicate that such enzymes may play a key role in the bioconversion of lignocellulose by termites. This work considers the presence of a redox lignocellulosic degradation and detoxification system supporting glicosil hydrolases. Enzymatic, electrochemical, microscopic and fermentative approaches were used in order to support this consideration. The host enzymes, endoglucanase (CgGH9-1), aldoketo reductase (CgAKR-1) and superoxide dismutase (CgSOD-1) were immunolocalizated in C. gestroi's digestive tract, confirming their presence in the insect digestomics. It was also found that supplementation with CgSOD-1, CgAKR-1, CgADH-1 (alcohol dehydrogenase) and CgLAC-1 (Laccase) enhanced saccharification of sugarcane bagasse performed by cellulosic cocktails. This synergism was based on reactive oxygen species generation. CgAKR-1 also showed to be a detoxifying agent against phenolic aldehydic inhibitors found in pretreated lignocelulose. A first putative animal LPMO from the family AA10 (CgAA10-2) was characterized and found capable of oxidizing cellulose. A glucose oxidase (CgGOX-1) was used in the development of a biobattery composed of sugars from sugarcane bagasse enzymatic hydrolysate. The catalase (CgCAT-1) showed high similarity with a catalase from R. flavipes. In general all identified enzymes could be related to the insect digestomics, reinforcing the role of termite endogenous redox enzymes on biomass degradation, xenobiotics detoxification and pro/anti-oxidant which contributes to understanding the termite biology. Finally, these enzymes present a great potential in biorefinaries, serving for multi-purpose applications and being considered as integrative enzymes by consolidating all processes in the production of second-generation ethanol (AU)

• FAPESP's process: 14/20576-7 - Characterization of auxiliary (redox) enzymes from the termite Coptotermes gestroi that cooperate with glycolytic hydrolases
• Grantee: Robson Tramontina
• Support Opportunities: Scholarships in Brazil - Master