Correction to: Butanol and butyric acid production from Saccharina japonica by Clostridium acetobutylicum and Clostridium tyrobutyricum with adaptive evolution.

Unfortunately, the author name was wrongly published as Pailin Sukwang.instead of Pailin Sukwong.

Butanol and butyric acid production from Saccharina japonica by Clostridium acetobutylicum and Clostridium tyrobutyricum with adaptive evolution.

Optimal conditions of hyper thermal (HT) acid hydrolysis of the Saccharina japonica was determined to a seaweed slurry content of 12% (w/v) and 144 mM H2SO4 at 160 °C for 10 min. Enzymatic saccharification was carried out at 50 °C and 150 rpm for 48 h using the three enzymes at concentrations of 16 U/mL. Celluclast 1.5 L showed the lowest half-velocity constant (Km) of 0.168 g/L, indicating a higher affinity for S. japonica hydrolysate. Pretreatment yielded a maximum monosaccharide concentration of 36.2 g/L and 45.7% conversion from total fermentable monosaccharides of 79.2 g/L with 120 g dry weight/L S. japonica slurry. High cell densities of Clostridium acetobutylicum and Clostridium tyrobutyricum were obtained using the retarding agents KH2PO4 (50 mM) and NaHCO3 (200 mM). Adaptive evolution facilitated the efficient use of mixed monosaccharides. Therefore, adaptive evolution and retarding agents can enhance the overall butanol and butyric acid yields from S. japonica.

Enhancement of biomass, lipids, and polyunsaturated fatty acid (PUFA) production in Nannochloropsis oceanica with a combination of single wavelength light emitting diodes (LEDs) and low temperature in a three-phase culture system.

A three-phase culture system combining blue (465 nm) light-emitting diode (LED) wavelength as the first phase, green (550 nm) as the second phase, and temperature stress as the third phase was applied to a Nannochloropsis oceanica culture in 14-L photobioreactors. Microalgal growth promotion parameters were optimized in the first phase, followed by green LED stress for lipid production in the second phase. Maximum biomass and lipid production values of 0.75 gdcw L-1 and 57.6% (w/w) were obtained at an aeration rate of 0.50 vvm, with a light intensity of 250 µmol m-2 s-1 and 24:0 h light/dark cycle. Culture temperatures of 15, 10 and 5 °C were applied in the third phase, where temperature stress induced the production of monounsaturated and polyunsaturated fatty acid synthesis in N. oceanica. The production of α-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid increased by 52% (w/w), 96% (w/w), and 77% (w/w), respectively, at 5 °C in the third phase.

Effects of wavelength mixing ratio and photoperiod on microalgal biomass and lipid production in a two-phase culture system using LED illumination.

Blue and red light-emitting diodes (LEDs) were used to study the effects of wavelength mixing ratios, photoperiod regimes, and green wavelength stress on Nannochloropsis salina, Isochrysis galbana, and Phaeodactylum tricornutum cell biomass and lipid production. The maximum specific growth rates of I. galbana and P. tricornutum were obtained under a 50:50 mixing ratio of blue and red wavelength LEDs; that of N. salina was obtained under red LED. Maximum cell biomass for N. salina and P. tricornutum was 0.75 and 1.07 g dcw/L, respectively, obtained under a 24:0 h light/dark cycle. However, the maximum I. galbana biomass was 0.89 g dcw/L under an 18:6 h light/dark cycle. The maximum lipid contents for N. salina, I. galbana, and P. tricornutum were 49.4, 63.3 and 62.0% (w/w), respectively, after exposure to green LED. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were obtained 1% in P. tricornutum and 2% in I. galbana.

Effects of light-emitting diode (LED) with a mixture of wavelengths on the growth and lipid content of microalgae.

Integrations of two-phase culture for cell growth and lipid accumulation using mixed LED and green LED wavelengths were evaluated with the microalgae, Phaeodactylum tricornutum, Isochrysis galbana, Nannochloropsis salina, and Nannochloropsis oceanica. Among the single and mixed LED wavelengths, mixed LED produced higher biomass of the four microalgae, reaching 1.03 g DCW/L I. galbana, followed by 0.95 g DCW/L P. tricornutum, 0.85 g DCW/L N. salina, and 0.62 g DCW/L N. oceanica than single LED or fluorescent lights at day 10. Binary combination of blue and red LEDs could produce the high biomass and photosynthetic pigments in the four microalgae. The highest lipid accumulation during second phase with the exposure to green LED wavelengths was 56.0% for P. tricornutum, 55.2% for I. galbana, 53.0% for N. salina, and 51.0% for N. oceanica. The major fatty acid in the four microalgae was palmitic acid (C16:0) accounting for 38.3-47.3% (w/w) of the total fatty acid content.