Industrial-scale culturing of the crude oil-degrading marine Acinetobacter sp. strain HC8-3S

• We cultured a marine crude oil-degrading bacterium on industrial scale.
• Fermentation conditions of Acinetobacter sp. strain HC8-3S were optimized.
• Shelf-life of fermentation broth was 120 d at 4 °C and 60 d at ambient temperature.
• The fermentation broth of HC8-3S can effectively degrade 94% crude oil in 5 days.

The marine bacterium Acinetobacter sp. strain HC8-3S, capable of degrading petroleum hydrocarbons, was previously shown to be applicable for bioremediation. Here, we evaluated the performance of the strain during industrial-scale fermentation, long-term storage, and biodegradation processes. Fermentation parameters were optimized for industrial-scale culturing using lower salinity and fewer inorganic salts in the culture medium. The shelf-life of the fermentation broth was evaluated in different storage conditions. Biodegradation efficiency of the strain was evaluated using gas chromatography. Results indicated that the optimum conditions for one-ton scale fermentation were 30 °C, pH 7.4–7.8, and rotation speed 90 rpm; the cell density reached 3.6 ± 1.9 × 1010 CFU ml−1 after 12 h. The low temperature can preserved fermentation broth for longer time. When the storage temperature was down to 4 °C from room temperature, half-life of strain HC8-3S extended from 9 days to 34 days. The biodegradation rate of the saturated hydrocarbon fraction of crude oil was 94% after treatment with the strain for 5 days. The results indicate that Acinetobacter sp. strain HC8-3S can be enriched efficiently on a large scale, making it a potentially useful industrial strain. This crude oil degradative capability of the strain HC8-3S provides possible application for the clean-up of crude oil-contaminated environment.