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Hydrogen emission by three wood-feeding subterranean termite species (Isoptera: Rhinotermitidae): Production and characteristics

Cao, Yueqing, Sun, Jian-Zhong, Rodriguez, Jose M., Lee, Karmen C.
Insect science 2010 v.17 no.3 pp. 237-244
Coptotermes formosanus, Reticulitermes flavipes, Reticulitermes virginicus, biotransformation, body weight, cellulose, digestive system, hydrogen, subterranean termites
Hydrogen emission by wood-feeding termites, Coptotermes formosanus, Reticulitermes flavipes and Reticulitermes virginicus, was investigated upon a cellulosic substrate as their food source. The emission rates among the three species tested were significantly different and R. virginicus demonstrated the greatest H₂ emission at 4.78 ± 0.15 μmol/h/g body weight. In a sealed test apparatus, H₂ emission for each termite species showed a quick increase at the initial incubation hours (3-6 h), followed by a slower growth, possibly due to the feedback inhibition by gas accumulation. Further investigation revealed that continuous H₂ emission could be maintained by reducing the H₂ partial pressure in the sealed container. The bioconversion of cellulose to molecular H₂ by the subterranean termites tested could reach as high as 3 858 ± 294 μmol/g cellulose, suggesting that the termite gut system is unique and efficient in H₂ conversion from cellulosic substrate.