Improved microbial conversion of de-oiled Jatropha waste into biohydrogen via inoculum pretreatment: process optimization by experimental design approach

Abstract

Improved microbial conversion of de-oiled Jatropha waste into biohydrogen via inoculum pretreatment: process optimization by experimental design approach In this study various pretreatment methods of sewage sludge inoculum and the statistical process optimization of de-oiled jatropha waste have been reported. Peak hydrogen production rate (HPR) and hydrogen yield (HY) of 0.36 L H2/L-d and 20 mL H2/g Volatile Solid (VS) were obtained when heat shock pretreatment (95 o C, 30 min) was employed. Afterwards, an experimental design was applied to find the optimal conditions for H2 production using heat-pretreated seed culture. The optimal substrate concentration, pH and temperature were determined by using response surface methodology as 205 g/L, 6.53 and 55.1 o C, respectively. Under these circumstances, the highest HPR of 1.36 L H2/L-d was predicted. Verification tests proved the reliability of the statistical approach. As a result of the heat pretreatment and fermentation optimization, a significant (~ 4 folds) increase in HPR was achieved. PCR-DGGE results revealed that Clostridium sp. were majorly present under the optimal conditions. Kumar et al. / Biofuel Research Journal 5 (2015) 209-214 Please cite this article as: Kumar G., Bakonyi P., Sivagurunathan P., Nemestóthy N., Bélafi-Bakó K., Lin C.Y. Improved microbial conversion of de-oiled Jatropha waste into biohydrogen via inoculum pretreatment and process optimization by experimental design approach. Biofuel Research Journal 5 (2015) 209-214.

Biohydrogen Production from Wastewaters

“…Among the various pretreatment methods, the heat-shock [11] pretreatment has been widely accepted as a suitable method for preparing the hydrogen-producing seed inocula, due to the relatively simple method for the suppression of the hydrogen consumers and selective enrich- Table 3. Inoculum pretreatment method for enriching hydrogen production mixed consortia.…”

Evaluation of different pretreatments on organic matter solubilization and hydrogen fermentation of mixed microalgae consortia

“…Visual characterization of the surface and interior morphology of pretreated algal cells was conducted using the scanning electron microscopy (SEM) (JSM-6500F, Japan Electron Optics Laboratory Co., Japan) and optical microscope (Nikon [24]. Subsequently, the vials were sealed with rubber stopper and aluminum cap and the vials were purged with N 2 gas for 5 min to ensure and maintain the strict anaerobic condition and then kept in an incubator with agitation speed of 120 rpm and desired temperature of 37 ± 0.1 C. During the culture period, gas production and gas composition in each of the vials were analyzed every day in the beginning and after sometimes two or three days once until the gas production stopped.…”

“…where HY was hydrogen yield (L/Kg VS added ), and HV H 2 was heating value of hydrogen (286 J/mmol) [24].…”

“…29.5 ± 0.8 mL/g VS added, respectively. Additionally, bioenergy production analysis [24], which is considered as main tool for the overall system evaluation is presented in Table 5. Peak energy production and yield were obtained with electrolysis pretreatment and the corresponding values were 2.65 ± 0.23 kJ/L-d and 0.43 ± 0.12 kJ/g VS added and the next peak values were attained with autoclave and ultrasonications with the values of 1.79 ± 0.09 kJ/L-d, 0.41 ± 0.10 kJ/g VS added and 1.44 ± 0.11 kJ/L-d, 0.32 ± 0.08 kJ/g VS added, respectively.…”

Thermodynamic evaluation of a photobioreactor for hydrogen production from syngas via a locally isolated Rhodopseudomonas palustris PT

“…Moreover, rapid depletion of fossil fuel reserves emphasizes the need for new and replenished energy resources [5,6]. Due to these reasons, tremendous amounts of investigation have been carried out worldwide to find eco-friendly and cost-effective renewable resources to meet the increasing global energy demand by minimizing their environmental impacts [7,8].…”