Application of Pretreatment, Bioaugmentation and Biostimulation for Fermentative Hydrogen Production from Maize Silage

Abstract

Bacteria produce hydrogen during anaerobic dark digestion of carbon rich natural resources including renewable cellulosic materials. The purpose of this work was to study the impact of maize silage pretreatment with Trichoderma fungi, bioaugmentation with defined bacterial inocula and/ or biostimulation with humic acids and an additional inorganic nitrogen source on the fermentative hydrogen production in laboratory batch assay. Experiments were carried out with and without Trichoderma asperellum pretreated silage. The selected bacterial inocula consisted of Clostridium, Enterobacter and Tissierella species, with or without Bacillus mycoides. Headspace gas composition, the amount of dry particulate matter, chemical oxygen demand and concentration of volatile fatty acids in liquid were determined. Bacterial communities were studied with fluorescence in situ hibridization. The predominant cultivable microbial species were isolated and identified. The study demonstrated a significant increase of hydrogen production from maize silage by indigenous bacteria after pretreatment with Trichoderma in comparison with silage untreated with Trichoderma. From tested factors, pretreatment, biostimulation with additional nutrients (ammonium nitrate and/ or humic acids) and bioaugmentation with defined bacterial inocula, pretreatment demonstrated significant improvement of hydrogen production from maize silage. Thereby, aerobic treatment with Trichoderma could be recommended for the pretreatment of silage for the purpose of fermentative production of hydrogen.

Selection and modification of microorganisms and substrates for acquiring and separation of energy carriers

“…Hydrogen usage as an energy carrier is the most important stone in hydrogen economy as it can store the energy from fossil domestic resources (natural gas, coal, oil), biomass and intermittently available renewables such as wind and Sun for use in stationary and mobile applications [1]. The information in this chapter is obtained from PhD thesis of Ilze Dimanta, defended in June, 2016, at the University of Latvia [2], MSc thesis of Sintija Valucka, defended in June 2015, Faculty of Biology, the University of Latvia [3], Bachelor's thesis of Zane Kleinmane, defended in June 2016, Faculty of Biology, the University of Latvia [4], Bachelor's thesis of Matīss Paiders defended in June 2017, Faculty of Biology, the University of Latvia [5], which to some extent is reflected in publications [6][7][8][9][10][11].…”