Value-added lipid production from brown seaweed biomass by two-stage fermentation using acetic acid bacterium and thraustochytrid

Abstract

Thraustochytrid production of polyunsaturated fatty acids and xanthophylls have been generally sourced from crop-derived substrates, making the exploration of alternative feedstocks attractive since they promise increased sustainability and lower production costs. In this study, a distinct two-stage fermentation system was conceptualized for the first time, using the brown seaweed sugar mannitol as substrate for the intermediary biocatalyst Gluconobacter oxydans, an acetic acid bacterium, along with the marine thraustochytrid Aurantiochytrium sp. to produce the value-added lipids and xanthophylls. Jar fermenter culture resulted in seaweed mannitol conversion to fructose with an efficiency of 83 % by G. oxydans and, after bacteriostasis with sea salts, production of astaxanthin and docosahexaenoic acid by Aurantiochytrium sp. KH105. Astaxanthin productivity was high at 3.60 mg/L/day. This new system, therefore, widens possibilities of obtaining more varieties of industrially valuable products including foods, cosmetics, pharmaceuticals, and biofuel precursor lipids from seaweed fermentation upon the use of suitable thraustochytrid strains.

Determination of Mannitol Decomposition Rate under Hydrothermal Pretreatment Condition

“…One of the constituents of kelp and a major target component is mannitol, which comprises the largest organic component of kelp. Mannitol is easily utilized by microorganisms for methane fermentation and valueadded oil production 7), 8) .…”

Removal of Acetic Acid from Bacterial Culture Media by Adsorption onto a Two-Component Composite Polymer Gel

“…Our study demonstrates an environmentally friendly, simple, and short-term method for the desorption of acetic acid. The recovered acetic acid is suitable for biological processes, such as fermentation using marine bacteria [ 25 ]. The NaCl concentration used for desorption (0.6 M) was close to the NaCl concentration in seawater.…”

Isolation of High Carotenoid-producing <i>Aurantiochytrium</i> sp. Mutants and Improvement of Astaxanthin Productivity Using Metabolic Information

“…We previously constructed a lipid fermentation system for Aurantiochytrium cells using waste syrup 27 and brown algae 25 as culture substrates. The main component of waste syrup is fructose, which is a good carbon source for Aurantiochytrium cells.…”

“…Biodiesel waste water 26 and high-fructose corn syrup 27 can also be utilized. We also reported the use of biomass, including shochu waste water 28 , waste syrup of canned fruits 29 , and brown macroalgae 25 . In this research, we newly isolated two Aurantiochytrium sp.…”