The majority of thermal modification processes are at temperatures greater than 180 °C, resulting in a product with some properties enhanced and some diminished (e.g., mechanical properties). However, the durability of thermally modified wood to termite attack is recognised as low. Recent attempts at combining thermal modification with chemical modification, either prior to or directly after the thermal process, are promising. Buffers, although not influencing the reaction systems, may interact on exposure to certain conditions, potentially acting as promoters of biological changes. In this study, two zwitterionic buffers, bicine and tricine, chosen for their potential to form Maillard-type products with fragmented hemicelluloses/volatiles, were assessed with and without thermal modification for two wood species (spruce and beech), with subsequent evaluation of their effect against subterranean termites (Reticulitermes grassei Clément) and their symbiotic protists. The effect of the wood treatments on termites and their symbionts was visible after four weeks, especially for spruce treated with tricine and bicine and heat treatment (bicine HT), and for beech treated with bicine and bicine and heat treatment (bicine HT). The chemical behaviour of these substances should be further investigated when in contact with wood and also after heat treatment. This is the first study evaluating the effect of potential Maillard reactions with zwitterionic buffers on subterranean termite symbiotic fauna.

Biotechnical Faculty University of Ljubljana SI 1000 Ljubljana Slovenia

cE3c Centre for Ecology Evolution and Environmental Changes Azorean Biodiversity Group University of the Azores 9700 042 Angra do Heroísmo Portugal

Department of Wood Processing and Biomaterials Faculty of Forestry and Wood Sciences Czech University of Life Sciences Prague Kamýcká 1176 16521 Praha 6 Suchdol Czech Republic

Department Wood Science and Engineering Luleå University of Technology Forskargatan 1 S 93197 Skellefteå Sweden

LEAF Research Centre Instituto Superior de Agronomia Universidade de Lisboa Tapada da Ajuda 1349 017 Lisboa Portugal

LNEC National Laboratory for Civil Engineering Structures Department Av do Brasil 101 1700 066 Lisbon Portugal

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