Charles Seo

Bioprocessing aspects of fuels and chemicals from biomass

This review deals with a recent development of biofuels and chemicals from biomass. Some of the grainbased biofuels and chemicals have already been in commercial operation, including fuel ethanol, biodiesel, 1.3-propanediol, polylactic acid (PLA) and polyhydroxy butyric acid/alkanoates (PHB/PHA). The next generation bioproducts will be based on lignocellulosics due to their abundance and to stabilize rising food prices. However, the technologies of handling biomass are yet in their infancy and suffer from low yield, low product titer, and low productivity. This review focuses on bioprocessing technologies for biofuels production: organic raw biomaterials available in Korea; volatile fatty acids platform, multi-stage continuous high cell density culture (MSC-HCDC), enrichment of fermentation broth by forward osmosis; various purification methods of pervaporation of ethanol, solvent extraction on succinic, lactic acids and reactive separation methods.

Improved volatile fatty acid and biomethane production from lipid removed microalgal residue (LRμAR) through pretreatment

Renewable energy from lipid removed microalgal residues (LRμARs) serves as a promising tool for sustainable development of the microalgal biodiesel industry. Hence, in this study, LRμAR from Ettlia sp. was characterized for its physico-biochemical parameters, and applied to various pretreatment to increase the biodegradability and used in batch experiments for the production of volatile fatty acids (VFA) and biomethane. After various pretreatments, the soluble organic matters were increased at a maximum of 82% in total organic matters in alkali-autoclaved sample. In addition, VFA and methane production was enhanced by 30% and 40% in alkali-sonicated and alkali-autoclaved samples, respectively. Methane heating value was recovered at maximum of 6.6 MJ kg(-1)VS in alkali-autoclaved conditions with comparison to non-pretreated samples. The pretreatment remarkably improved LRμAR solubilization and enhanced VFA and biomethane production, which holds immense potential to eventually reduce the cost of algal biodiesel.

Improvement of fermentative production of exopolysaccharides from Aureobasidium pullulans under various conditions

The optimization of exopolysaccharide (EPS) production was investigated in the polymorphic fungal strain of Aureobasidium pullulans (KCTC 6081) with varying pH, nutrients concentration, and mixing parameters in batch fermentation condition. The maximum production of EPS (∼7.5 g/L) was observed at pH 4, while optimum nutrient concentration of carbon (sucrose), nitrogen (NaNO3), phosphorous (K2HPO4), and ascorbic acid was 50 g/L, 5 g/L, 1 g/L and 2 g/L, respectively. Interestingly, EPS productivity under non pH controlled fermentation conditions was 0.12 g/L/h with 400 rpm mixing, while under a controlled pH of 4, the EPS productivity was 0.21 g/L/h with 600 rpm, respectively. The fed-batch fermentation increased the EPS productivity up to 0.345 g/L/h with changing mixing conditions from 200 to 600 rpm and reached 47 g/L with 88% pullulan. Thus, pH and mixing were the key parameters for enhancing EPS production from A. pullulans. It is expected that these optimized parameters can be well used for enhanced industrial production of pullulan.