Understanding the cumulative effects of salinity, temperature and inoculation size for the design of optimal halothermotolerant bioanodes from hypersaline sediments

Refka Askri (1) , Benjamin Erable (2) , Mohamed Neifar (1) , Luc Etcheverry (2) , Ahmed Slaheddine Masmoudi (1) , Ameur Cherif (1) , Habib Chouchane (1)

1 UMA - Université de la Manouba [Tunisie]
2 LGC - Laboratoire de Génie Chimique

The main objective of this study was to understand the interaction between salinity, temperature and inoculum size and how it could lead to the formation of efficient halothermotolerant bioanodes from the Hypersaline Sediment of Chott El Djerid (HSCE). Sixteen experiments on bioanode formation were designed using a Box-Behnken matrix and response surface methodology to understand synchronous interactions. All bioanode formations were conducted on 6 cm2 carbon felt electrodes polarized at −0.1 V/SCE and fed with lactate (5 g/L) at pH 7.0. Optimum levels for salinity, temperature and inoculum size were predicted by NemrodW software as 165 g/L, 45 °C and 20%, respectively, under which conditions maximum current production of 6.98 ± 0.06 A/m2 was experimentally validated. Metagenomic analysis of selected biofilms indicated a relative abundance of the two phyla Proteobacteria (from 85.96 to 89.47%) and Firmicutes (from 61.90 to 68.27%). At species level, enrichment of Psychrobacter aquaticus, Halanaerobium praevalens, Psychrobacter alimentaris, and Marinobacter hydrocarbonoclasticus on carbon-based electrodes was correlated with high current production, high salinity and high temperature. Members of the halothermophilic bacteria pool from HSCE, individually or in consortia, are candidates for designing halothermotolerant bioanodes applicable in the bioelectrochemical treatment of industrial wastewater at high salinity and temperature.

Mots clés: Hypersaline sediment; Halothermotolerant bioanodes; Response surface methodology; Metagenomics analysis; Statistical confrontation

Domaines: Génie chimique; Génie des procédés

Refka Askri, Benjamin Erable, Mohamed Neifar, Luc Etcheverry, Ahmed Slaheddine Masmoudi, et al.. Understanding the cumulative effects of salinity, temperature and inoculation size for the design of optimal halothermotolerant bioanodes from hypersaline sediments. Bioelectrochemistry, 2019, 129, pp.179-188. ⟨10.1016/j.bioelechem.2019.05.015⟩. ⟨hal-02291096⟩