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Biotechnology and Bioprocess Engineering 16: 1231-1239 (2011) DOI 10.1007/s12257-011-0278-1
RESEARCH PAPER
Fermentation of Seaweed Sugars by Lactobacillus Species and the Potential of Seaweed as a Biomass Feedstock
Hyeong Jin Hwang, Shin Youp Lee, Suk Min Kim, and Sun Bok Lee
Received: 23 June 2011 / Accepted: 2 July 2011 The Korean Society for Biotechnology and Bioengineering and Springer 2011
Abstract It is known that seaweeds differ greatly from land plants in their sugar composition. The current research on the L-lactic acid fermentation process focuses on land plant sugars as a carbon source, with the potential of seaweed sugars being largely ignored. This study examined the feasibility of seaweed biomass as a possible carbon source for the production of L-lactic acid, by comparing the fermentation of seaweed sugars (D-galactose, D-mannitol,
L-rhamnose, D-glucuronic acid, and L-fucose) and land plant sugars (D-glucose, D-xylose, D-mannose, and L-arabi-nose). The experiments were repeated with 2 sugar acids (D-gluconic acid, D-glucaric acid) in order to investigate the effect of the degree of reduction of carbon source on the fermentation yield. This research also examined the effect of bacterial strain on the characteristics of fermentation reactions, by conducting L-lactic acid fermentation with 7 different Lactobacillus species. Taking into account the sugar composition of seaweed and the levels of lactic acid production from each pure sugar, it was possible to predict the lactic acid production yield of various seaweeds and land plants. From comparative analysis of the predicted lactic acid production yield, it was found that seaweeds are already comparable to lignocellulosics at the current stage of technology. If new technologies for the utilization of non-fermentable seaweed sugars are developed, seaweeds show promise as an even more useful biomass feedstock than lignocellulosics.
Keywords: seaweed, lactic acid fermentation, Lactobacillus, degree of reduction, biomass feedstock
1. Introduction
Lactic acid is one of the most important organic acids widely used in the food, pharmaceutical, leather, and textile industries [1]. In recent years, the demand for lactic acid has increased considerably, due to its novel application as a monomer in the preparation of polylactic acid (PLA), an environment-friendly alternative to petrochemicals plastics[2]. PLA has tremendous advantages, such as biodegrad-ability, thermoplasticity, and high strength. These advantages depend on optical isomers and its optical properties are very important in PLA...