Oplopanax elatus adventitious root production through fed-batch culture and their anti-bacterial effects

Fed-batch culture (FBC) is extensively used in microbial culture to achieve a high yield of the desired products. However, the FBC application is less in plant cells or organs because of relatively complex chemical components in the culture medium. To develop the FBC of adventitious roots (ARs) of Oplopanax elatus, the present study designed two FBC systems, where the initial culture media were controlled as 3 L of half- (FBC1) and full-strength (FBC2) of Murashige and Skoog medium, and the culture efficiency was compared with the batch culture (BC). The result showed that AR biomass and bioactive compound accumulation were favorable in both FBC systems compared with those in the BC system. Between FBC1 and FBC2, a significant difference was exerted, with the former showing a good culture efficiency, and 5381.6 mg l−1 of total polysaccharides and 950.8 mg l−1 of total flavonoids were produced in FBC1. In addition, the anti-bacterial property of O. elatus ARs was evaluated for their further using in the production of relative products. The extract from FBC1-cultured ARs (OAE) inhibited growth of bacteria including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis, and a higher anti-bacterial effect was found on E. coli. Consequently, the effects of OAE on cell permeability and oxidative respiratory metabolism of E. coli were investigated. The levels of alkaline phosphatase activity, nucleotide or protein leakage, and electrical conductivity in the bacterial substrate were increased by the OAE treatment, illustrating that OAE changed the permeability of cell membranes or walls of E. coli. Simultaneously, OAE inhibited the respiratory of E. coli and a low superposition rate (30.5%) was found in the combination group of OAE with sodium phosphate. Furthermore, the activity of the key enzyme (glucose-6-phosphate dehydrogenase) in the hexose monophosphate (HMP) pathway was obviously decreased by the OAE treatment, confirming that OAE exerts its anti-bacterial effect on E. coli by regulating the HMP pathway. Fed-batch culture improves culture efficiency of Oplopanax elatus adventitious roots. Large amounts of polysaccharides and flavonoids were produced in fed-batch culture. Adventitious roots possessed higher anti-bacterial effect against Escherichia coli. Cell permeability of Escherichia coli were changed by treatments of adventitious root extracts. Extracts inhibited respiratory of Escherichia coli by affecting hexose monophophate pathway.