Enhanced dark fermentative biohydrogen production from marine macroalgae Padina tetrastromatica by different pretreatment processes

M Radha,A.G Murugesan

doi:10.18331/brj2017.4.1.5

Abstract

Marine macroalgae are promising substrates for biofuel production. Pretreating macroalgae with chemicals could remove microbial inhibitors and enhance the accessibility of the microorganisms involved in the process to the substrates leading to increased product yield. In the present study, Padina tetrastromatica a seaweed species was subjected to different chemical pretreatment in order to remove phenolic content and to enhance biohydrogen production. Different mineral acids (i.e., HCl, H2SO4, and HNO3) and bases (NaOH and KOH) were applied for effective pretreatment of the seaweed. Dilute sulphuric acid treatment of seaweed resulted in the highest cumulative biohydrogen production of 78 ± 2.9 mL/0.05 g VS and reduced phenolic content to 1.6 ±0.072 mg gallic acid equivalent (GAE)/g. Optimization of three variables for pretreatment (i.e., substrate concentration, acid concentration, and reaction time) was examined by Response Surface Methodology. After the optimization of the pretreatment conditions, phenolic content was decreased to 0.06 mg GAE/g. and enhanced biohydrogen production was observed. Structural changes due to pretreatment was studied by FTIR and XRD analyses. The results clearly indicated that the dilute sulphuric acid pretreatment was effective in removing phenolic content and enhancing biohydrogen production.

Highlights

The search for future renewable and clean energy carriers is increasingly focused on hydrogen mainly due to its environmentally-friendly nature and the fact that it burns clean
The seed inoculum used for biohydrogen production was isolated from the sewage sludge
In a previous study, undefined bacterial consortium obtained from sewage sludge was used for biohydrogen production from a seaweed Laminaria japonica (Park et al, 2009)

Summary

Introduction

The search for future renewable and clean energy carriers is increasingly focused on hydrogen mainly due to its environmentally-friendly nature and the fact that it burns clean. Several modes of hydrogen productions have been widely investigated employing various chemicals and biomass resources (Lakshmikandan and Murugesan, 2016a). Biological hydrogen production could be attained by using microalgae as well as photosynthetic and fermentative bacterial strains (Li et al, 2004; Ren et al, 2006). Fermentative biohydrogen production technology is based on the utilization of biomass as raw material to produce fuel hydrogen. Selection of raw materials for large scale biohydrogen production is based on a number of factors including availability, renewability, cost, carbohydrate content, and biodegradability (Kapdan and Kargi, 2006). Cultivation of biomass on land for fuel can lead to negative impacts on food production economy. It has shown that marine resources (e.g., seaweeds and seagrass) could be used as sustainable replacements for food grains in biofuels production (Carlsson, 2007; Vergara-Fernández et al, 2008)

Methods

Results

Conclusion