The potential of a Lactiplantibacillus plantarum strain to improve yield of tea tree seed oil through fermentation process.

Great mass of tea tree seeds (TTS) are naturally rotted away as agricultural waste because there is no suitable technology used for extracting oil from TTS. The fermentation method is a new process and that can simultaneously recover oil, starch and saponins from TTS. In this study, a key bacterial strain named JJZ21 was isolated from fermented TTS milk (ground TTS and water) by the serial dilution method and identified as Lactiplantibacillus plantarum strain through molecular analyses. The production of cellulase, pectinase, amylase and protease of JJZ21 were visualized on agar plates containing specific enzyme substrates. Compared with the control, addition treatment with JJZ21 dramatically improved the activities of cellulase, pectinase, amylase and protease, reduced content of soluble sugar, protein and dry matter and pH in the TTS milk, shortened the fermentation time and increased the yield of TTS oil. Meanwhile, the addition of JJZ21 had no significant effect on quality of TTS oil. However, the yield of TTS oil decreased with excessive fermentation. Response surface methodology was used to evaluate the optimum conditions for fermentation process to obtain the maximum oil yield.