Vol.:(0123456789) 1 3 Waste and Biomass Valorization https://doi.org/10.1007/s12649-017-0186-5 ORIGINAL PAPER Analysis of an Ionic Liquid and Salt Tolerant Microbial Consortium Which Is Useful for Enhancement of Enzymatic Hydrolysis and Biogas Production Prapakorn Tantayotai 1  · Kittipong Rattanaporn 2  · Surapun Tepaamorndech 3  · Kraipat Cheenkachorn 4  · Malinee Sriariyanun 5 Received: 8 June 2017 / Accepted: 27 December 2017 © Springer Science+Business Media B.V., part of Springer Nature 2017 Abstract Production of biofuels and biochemicals from lignocellulosic biomass via biorefning process requires both efcient pretreat- ment and cellulase enzymes to improve saccharifcation. Ionic liquid (IL) pretreatment is one of the competent methods to modify recalcitrant structures of lignocellulosic biomass, however, IL inhibits cellular metabolisms and cellulase activities. In this study, a lignocellulose degrading microbial consortium, named CT-1, was newly bred from saline soil sample by successive subcultivations and was cultured to produce IL-tolerant cellulase enzymes. The CT-1 showed high degradation activity on various cellulosic substrates, including rice straw, corn stover, and mixed vegetable residues. In the presence of 1 M of an IL, 1-ethyl-3-methylimidazolium acetate (EMIM-Ac), activity of cellulase produced from CT-1 remained more than 95% of non-IL condition. For application in biogas production, the CT-1 was mixed with activated wastewater sludge and rice straw residues in batch anaerobic digester. Addition of CT-1 enhanced biogas production for 6.5 times (170.92 mL/g- VS) compared to the control batch. The bacterial population distribution of CT-1 was analyzed by quantitative PCR with specifc primers and the results showed that Bacteroidetes, Actinobacteria and Methanosarcinales were major members that corresponding with the activities of biomass degradation and biogas production. Overall, these results demonstrated the potential of CT-1 in biorefning process of lignocellulosic biomass with compatibility to IL pretreatment. Keywords Microbial consortium · Cellulase · Ionic liquid tolerance · Salt tolerance · Biogas · Lignocellulosic biomass Introduction Lignocellulosic biomass is currently targeted to be one of the potential raw materials for biorefning process to pro- duce biochemical specialties including biofuels [1, 2]. Rice straw residue, as an example of lignocellulosic biomass, is mostly left unused in the rice feld after harvesting season. It is bulky biomass that is difcult for transportation to the storage for biorefning process. Typically, it is open-air burnt down or naturally degraded by microorganisms, and as a result greenhouse gases including methane and carbon dioxide are released to environment. In Thailand, in 2015, about 60 million metric tons of rice straws were produced and 27 million metric tons of uncontrolled greenhouse gas could be generated and released. This leftover rice straw was estimated to yield potential energy capacity up to 7.35 × 10 7 GJ [3]. Therefore, utilization of lignocellulosic biomass has been tremendously developed in these recent years to miti- gate the environmental impacts and to improve economic * Malinee Sriariyanun macintous@gmail.com 1 Department of Microbiology, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand 2 Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand 3 Food Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, Pathumthani 12120, Thailand 4 Department of Chemical Engineering, Faculty of Engineering, KMUTNB, Bangkok 10800, Thailand 5 The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), KMUTNB, Bangkok 10800, Thailand