An alternative carbon source from konjac powder for enhancing production of bacterial cellulose in static cultures by a model strain Acetobacter aceti subsp. xylinus ATCC 23770

Abstract

A new carbon source for bacterial cellulose production was successfully developed from konjac powder by using dilute acid hydrolysis and was detoxified by different alkaline treatment methods to remove microbial growth inhibitors. The various treatments included the addition of calcium hydroxide or sodium hydroxide to pH 10, and subsequent adjustment of the pH to 5 with acid as well as treatment with activated charcoal or laccase, respectively. The results showed that the detoxification effect using Ca(OH) 2 was much better than that using NaOH. If activated charcoal or laccase was added in the process, the detoxification effects would go further and bacterial cellulose production could be improved more. Based on the same concentration of total sugars, bacterial cellulose production using the hydrolyzates was three times higher than that using glucose, six times higher than that using mannose, and five times higher than that using glucose–mannose mixture as carbon source in static cultures. The addition of extra calcium in glucose media in the form of CaCl 2 at pH 5 did result in an improvement of less than 50% in BC production, which was not comparable to the Ca(OH) 2 treatments at pH 10. The possible mechanisms behind the findings were discussed and potential stimulatory factors for the fermenting bacterium formed during the alkaline processing deserve further attention. The results indicate that konjac powder could serve as a feedstock for bacterial cellulose production and cultivation of Amorphophallus rivieri Durieu would bring more economic benefits to farmers in future.