Bioconversion of waste office paper to hydrogen using pretreated rumen fluid inoculum

Abstract

In this study, a microbial consortium from an acid-treated rumen fluid was used to improve the yields of H production from paper residues in batch reactors. The anaerobic batch reactors, which contained paper and cellulose, were operated under three conditions: (1) 0.5 g paper/L, (2) 2 g paper/L, and (3) 4 g paper/L. Cellulase was added to promote the hydrolysis of paper to soluble sugars. The H yields were 5.51, 4.65, and 3.96 mmol H/g COD, respectively, with substrate degradation ranging from 56 to 65.4 %. Butyric acid was the primary soluble metabolite in the three reactors, but pronounced solventogenesis was detected in the reactors incubated with increased paper concentrations (2.0 and 4.0 g/L). A substantial prevalence of Clostridium acetobutylicum (99 % similarity) was observed in the acid-treated rumen fluid, which has been recognized as an efficient H-producing strain in addition to ethanol and n-butanol which were also detected in the reactors.

Bioconversion of Cellulose Into Hydrogen, Biogas and Organic Acids Using Microbial Consortium From a Pulp and Paper Mill Wastewater Treatment Plant

“…Botta et al 8 also observed this trend. These authors used paper as substrate for hydrogen production, cellulase for substrate conversion, and obtained 56 to 65% of soluble carbohydrate consumption for concentrations from 0.5 to 4.0 g L -1 of paper and pretreated rumen fluid as inoculum.…”

“…In contrast, the hydrogen production potential (P) decreased from 39. , respectively. However, Botta et al 8 reported that the conversion of the cellulosic biomass into hydrogen was possible only after the addition of commercial cellulase enzyme, which was not applied in the present study.…”

“…The presence of these acids in the fermentation of cellulosic material has been widely reported. 8,9,32 In C2, which had the highest hydrogen production (39.25 mmol L The organic acids as a function of the operational period of the batch reactors for the three tested cellulose concentrations are described in the Table 1.…”

“…Many studies have reported the use of commercial cellulase to promote the biomass hydrolysis. Botta et al 8 observed that the hydrogen production using paper as substrate and rumen fluid as inoculum was only possible after the application of commercial cellulase. Similarly, Datar et al 14 also described the hydrogen production from hydrolyzed corn stover and anaerobic digester sludge as inoculum using commercial cellulase.…”

“…3,4 Some bacteria of the genera Clostridium, Bacillus, Ruminococcus, Enterobacter have been widely described as cellulose-degrading bacteria. [5][6][7] These bacteria, as well as the non-cellulolytic one, are found in different anaerobic environments such as rumen, 8 landfill leachate, 9 vegetable wastes 10 and soil. 11 The non-cellulolytic bacteria may contribute to cellulose biodegradation by controlling pH and consuming metabolites, factors which affect the cellulolytic activity by enzyme inhibition and/or metabolite repression.…”