The hydrolysis of lignocellulosic biomass results in the production of so-called fermentation inhibitors, which reduce the efficiency of biohydrogen production. To increase the efficiency of hydrogen production, inhibitors should be removed from aqueous hydrolysate solutions before the fermentation process. This paper presents a new approach to the detoxification of hydrolysates with the simultaneous formation of in-situ deep eutectic solvents (DES). In the first stage of the study, inhibitors were identified in the real hydrolysate samples using highperformance liquid chromatography (HPLC). Four monoterpenes were tested for their potential to extract furfural (FF) with simultaneous DES formation. An optimization process of the most important parameters affecting the extraction process and DES formation (Thymol:FF) was conducted using the Central Composite Design (CCD) model. A temperature of 40 °C, pH of 7, mHBD:mHYD ratio of 2:1, and time of 50 min were selected as the optimal conditions. These results indicate the high efficiency of FF removal from hydrolysates (92.1 - 94.6 %) in a onestep process. Meanwhile, the structural properties of the formed DES measured by Fouriertransform infrared spectroscopy (FT-IR) and Nuclear magnetic resonance spectroscopy (NMR) differed only slightly from those of the DES composed of pure substances (Furfural and Thymol).

Current efforts are taken to increase resource efficiency, close material loops, and improve sustainable waste and by-products management. Thus, networking agro-food by-products andc onverting them into valuable products completely exhausting the potential of the raw material becomes significant. Model lignocellulosic and starch based biomass were subjected to pre-treatment with the application of acidic compounds, i.e. sulphuric (SA) and acetic (AA) acids. The response, i.e. total sugar content and derivatives content is investigated depending on variables changed during hydrolysis: concentration of acid, process duration, temperature and the size of the biomass particles. After saccharification, the hydrolysates were analysed via HPLC. Total reducing sugars concentration was in the range of 0.1 – 15.53 g/LAmong the substances present in the hydrolysates, protein, peptides, hydroxybenzyl acid (HA), 5-HMF, furfural (FF), vanillin (V), vanillic acid (VA), formic acid (FA) and levulinic acid (LA) were found in the range of 0.44 – 9.05 g/L and determined as total derivatives concentration. The aim of the study was to evaluate the measurable effects of the research and deliver information about the statistically important parameters for the process course and relations between the variables.

This work presents results of investigations on biotrickling filtration of air polluted with cyclohexane co-treated in binary, ternary and quaternary volatile organic compounds (VOCs) mixtures, including vapors of hexane, toluene and ethanol. The removal of cyclohexane from a gas mixture depends on the physicochemical properties of the co-treated VOCs and the lower the hydrophobicity of the VOC, the higher the removal efficiency of cyclohexane. In this work, the performance of biotrickling filters treating VOCs mixtures is discussed based on surface tension of trickling liquid for the first time. A mixed natural – synthetic packing for biotrickling filters was utilized, showing promising performance and limited maintenance requirements. Maximum elimination capacity of about 95 g/(m ³·h) of cyclohexane was reached for the total VOCs inlet loading of about 450 g/(m ³·h). This work presents also a novel approach of combining biological air treatment with management of a spent trickling liquid in the perspective of circular economy assumptions. The waste liquid phase was applied to the plant cultivation, showing a potential for e.g. enhanced production of energetic biomass or polluted soil phytoremediation.