Metabolite profiling and pathway prediction of laver (Porphyra dentata) kombucha during fermentation at different temperatures

•Metabolites of laver kombucha at different fermentation conditions was studied.•Accumulation of phenolic compounds and organic acids was found after fermentation.•Most of amino acids degraded at the end of fermentation for both conditions.•Higher metabolite accumulation was observed at lower temperature.•Pathway prediction was explored for laver kombucha fermentation for the first time. This study is aimed to explore the impact of fermentation temperature on laver kombucha by profiling the accumulation and degradation of metabolites and elucidating their related pathways of metabolism. Laver kombucha was produced through ultrasound-assisted extraction and fermentation using a biofilm called SCOBY at 25 and 30 °C (hereafter named K-25 and K-30, respectively) for 14 days. Overall, organic acids, soluble sugars, amino acids, and phenolic compounds were found to participate in the biosynthesis pathway. The level of amino acids showed a decreasing trend, except taurine in the K-30. At day 14, phenolic compounds (pyrogallol, ρ-hydroxybenzoic acid, ρ-coumaric acid, salicylic acid, rutin, and naringin) were accumulated in both samples. Although it showed a similar trend, K-25 exhibited a higher metabolite accumulation tendency than K-30. This comprehensive characterization of the dynamic changes of metabolites and pathway prediction can pinpoint the influence of the fermentation conditions on the biosynthesis of secondary metabolites.