Lignocellulose degradation by microbial consortia from phytophagous insect guts: microbial diversity and enzymatic activities

Insects are the world’s tiniest, most efficient bioreactors known to transform lignocellulose.  They have optimized their digestion in highly efficient systems [1, 2]. Until recently, the field of insects biology and biochemical engineering were far apart. Nevertheless, much of this knowledge is relevant to today’s biorefinery challenge. The study of original strategies implemented in insect guts would be of interest to improveme biomass conversion. The processes involved during digestion and the interplay between the different digestive compartments, notably in terms of microbes and enzymes action, mastication and fragmentation and abiotic effectors are still unknown.

The aim of this work is to compare and taming the action of microbial and enzymatic consortia that allow efficient lignocellulose degradation. For this, with a biomimetic approach, the digestive microbiomes of three insects (Gromphadorrina potentosa, Potosia cuprea, and Locusta migratoria) were implemented in fed-batch reactors.

The microbiomes of insect guts were successfully maintained in bioreactors and the dynamics of lignocellulose degradation was followed. Their ability to degrade lignocellulosic substrate (wheat straw) as well as their microbial and enzymatic diversity allowed comparing the efficiency of these potential bioressources. The results shows that the microbiomes implemented in reactor degraded around 20% of the biodegradable part of LC.  The microbial diversity is quite the same at the beginning and at the end of the batches showing no specific simplifications of the microbiome.

This research will enable to identify microbial and enzyme activities efficient for lignocellulse degradation and to design biomimetically specific enzyme cocktails.

1. Martin (1983)

2.Godon (2013)