Valorization and characterization of Camellia sp. fruit husks through autohydrolysis: bioactive compounds, cosmetics and bioethanol production

Autohydrolysis is a green technology know for its efficiency as to several approaches. However, its mostly done alone or paired with an organic solvent method. This study explored the effects of two autohydrolysis stages of Camellia seed husks at varying temperatures (140–220 °C) and solid-to-liquid ratios (1:8 and 1:30 w / v ). Liquid fractions were rich in phenolics, obtaining the highest value at 140 °C (23.8 ± 0.01 g GAE/100 g DW), which was subjected to an antimicrobial assay against methicillin-resistant Staphylococcus aureus (MRSA); with peak antioxidant capacity at 160 °C (TEAC: 34.0 ± 0.2 g TroloxE/100 g DW; FRAP: 11.8 ± 0.2 g BHTE/100 g DW), both in the first stage. The second-stage increased xylose recovery up to 59.5 %. This fraction was subjected to a probiotic assay using lactic acid bacteria. Selected extracts were also used to develop creams with suitable mechanical characteristics. Fermentability of pretreated solids was carried out. Pre-saccharification released 27.24 ± 1.2 g/L glucose from 200 °C-treated biomass, compared to 9.09 ± 0.3 g/L at 140 °C. Ethanol production reached 18.56 ± 0.79 g/L after 48 h fermentation with the 200 °C sample, while remaining below 3.8 ± 0.6 g/L for the 140 °C-treated material. These findings demonstrate that autohydrolysis not only enables selective recovery of bioactives for health benefits, but is also adequate for bioethanol production, highlighting its biorefinery potential. • Hydrothermal processing of Camellia seed husks was made at 140–220 °C. • Extracts were rich in xylose, arabinose, saponins, and phenolics. • Lactobacillus fermentum and L. plantarum improved growth at 0.5–1 %. • Antimicrobial screening revealed a minimum inhibitory concentration at 1.5–2 mg/mL. • Ethanol production reached 18.56 ± 0.79 g/L after 48 h fermentation.