Integrated Approach for Development of Environmental Biotechnologies for Treatment of Solid Organic Waste and Obtaining of Biohydrogen and Lignocellulosic Substrate

Abstract

Solid food waste is a significant threat to the environment. Thermodynamic calculations allow determining theoretically possible metabolic pathways for degradation of organic compounds by microorganisms, and also to select the optimal one to increase efficiency of food waste recycling. The purpose of our work was application of thermodynamic calculations to find out suitable fermentation parameters for regulation of microbial metabolism to ensure high rate of waste decomposition and formation of valuable products. The following methods were used:  for pH and oxidation-reduction potential (ORP) measuring – colorimetric and potentiometric, for volume and composition of synthesized gas study – volumetric and chromatographic, for fermentation parameters calculation – mathematical. Fermentation of multicomponent kitchen food waste under theoretically calculated optimal parameters pH = 7.0 and Eh = –250...–350 mV provided extremely high metabolic activity of hydrogen-producing microbial community which resulted in decrease in duration of batch fermentation from to 3 days, increase in hydrogen yield from 16 to 80-115 L/kg of dry waste. The coefficient of waste destruction (Kd) that is ratio of initial and final weight of waste reached 91. Obtained after fermentation unfermented lignocellulosic substrate was shown to be applied as plant probiotics and supply mineral nitrogen for plant nutrition in arid condition. Thus, high efficiency of application of thermodynamic prognosis method of microbial interaction with organic compounds was shown to become the base for biotechnology of destruction of environmentally hazardous solid food waste with simultaneous obtaining of valuable products: environmentally friendly energy carrier – molecular hydrogen, as well as lignocellulosic substrate to increase crop yields.

DOI: http://dx.doi.org/10.5755/j01.erem.74.4.20723