Termites as a tool to improve lignocellulose biomass valorization : study of enzymatic complex in termites and its common symbionts by comprehensive metabolite profiling

Conference (2012, November 16)

Termites artificially-fed on unusual diet and resulting enzymatic switches

Poster (2012, August)

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as ... [more ▼]

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as starch. The production of putative endogenous α - amylase has been previously shown in R. flavipes, as the disappearance of the major symbiotic flagellates from the hindgut. Here, we compared enzymatic activities (CMCase, MCCase, xylanase, amylase, α- and β-glucosidase) between different fractions of the digestive tract of starch-, cellulose-, and wood-fed termites. Main compounds of the artificial diets, namely starch or MCC, resulted in differential enzymatic activity. Even the substitution of wood by artificial diets itself seemed to induce changes in enzymatic activities, regardless of the main substrate in the diet, as we observed strong midgut α-glucosidase activity only for artificially-fed termites. Preliminary assays to isolate and characterize enzymes were performed using proteomic methods. [less ▲]

Termites as a tool to improve lignocellulose biomass valorization: study of enzymatical complex from termites and its common symbionts by comprehensive metabolite profiling.

Conference (2012, May)

Changes in termites feeding diets for gut micro-organisms selection and further cultivation

Poster (2011, October 02)

Termites gut may overcome important dietary perturbations, initial diversity acting as key point buffering effects on host, although termites possess their own enzymatic system. Some artificial diets ... [more ▼]

Termites gut may overcome important dietary perturbations, initial diversity acting as key point buffering effects on host, although termites possess their own enzymatic system. Some artificial diets permitted a simplification of the lower termites gut symbiotic system, which could be used as first step in symbionts isolation and cultivation. Preliminary assay of cultivation actually gave encouraging results. Proteomic proved to be suitable tool to investigate such a complex system. Nevertheless, for some symbionts very few genes are sequenced, which should lead to more targeted proteomic studies. Protein chromatography will allow to split up the proteome and more accurate analysis. [less ▲]

BIOREMEDIATION DE SOLS POLLUES AUX HYDROCARBURES – AMELIORATION DE LA BIOREMEDIATION IN SITU DES HYDROCARBURES PAR BIO-AUGMENTATION AU MOYEN DE SOUCHES ENDOGENES ET EXOGENES

Master's dissertation (2010)

This study relates to biological treatment of hydrocarbon polluted soils. Its purpose is to establish an industrial approach of bioaugmentation and to verify its efficiency compared with biostimulation ... [more ▼]

This study relates to biological treatment of hydrocarbon polluted soils. Its purpose is to establish an industrial approach of bioaugmentation and to verify its efficiency compared with biostimulation. The purpose is to simulate in situ bioremediation using experimental columns. It has been demonstrated that it’s possible to produce a biomass able to degrade hydrocarbons in a polluted soil in one month. The main way of hydrocarbon elimination in the soil is biodegradation and the amount of hydrocarbons removed by water is negligible (1 % in each case). The addition of exogenous strains into the soil leads to the best biodegradation rate (39,3 % in 63 days). An endogenous bioaugmentation was tried but the efficiency was not demonstrated. On the other hand, the use of an artificial consortium was not more satisfying. Biostimulation alone led to a biodegradation rate of 23,9 % in 63 days. The lack of oxygen was avoided and evaluated through nitrite and ammonium concentrations in the water. These concentrations were negligible and always less than 2,5 and 1 mg/l, respectively. This work also tried to develop a special technique of monitoring of microbial ecology with microplates (Biolog ECO Micro PlateTM). The results were analysed through two different statistical methods : similarity rates and principal component analysis. It has been demonstrated that the column which leads to the best biodegradation rate also shows a particular metabolic profile, according to principal component analysis. The similarity rate is only 31 % with the initial microflora. This microflora seems to change during the experience because the similarity rate between the initial and the final microfloras is only 61 %. This work proved the efficiency of exogenous bioaugmentation compared with biostimulation. It proposes to apply this technique on a large scale, but only if the amount of polluted soil is evaluated before. [less ▲]