Sugarcane bagasse hydrolysate valorization through crude bioemulsifier production and concentration-dependent modulation of lettuce early development

Sugarcane bagasse is an abundant lignocellulosic residue whose hemicellulosic fraction can support fermentation for value-added bioproducts, but agricultural responses to crude bioemulsifiers from this stream remain poorly explored. This study produced and characterized a solvent-washed, non-dialyzed crude bioemulsifier (crude BE) by Scheffersomyces shehatae 16-BR6-2AI in a sugarcane bagasse hemicellulosic hydrolysate (SBHH)-based medium supplemented with soybean oil and evaluated concentration-dependent effects on Lactuca sativa early development. After 144 h, broths from three flasks were pooled for recovery. The preparation yielded 18.0 g L −1 crude BE and contained 54.7 ± 1.2% carbohydrates, 37.7 ± 1.0% proteins, and 7.6 ± 0.5% lipids. At 1000 mg L −1 , EI₂₄ and EI₁₆₈ were 59.3 ± 2.1% and 51.8 ± 1.9%, respectively, corresponding to 87.4% retention. In filter-paper assays, 500 mg L −1 resulted in 100% final germination, a germination speed index of 33.92, a mean germination time of 2.14 d, and a radicle length of 61.66 ± 1.32 mm versus 50.30 ± 1.60 mm in the control. At 5000–10,000 mg L −1 , germination was delayed and seedling growth was restricted despite 93.33% final germination. A complementary horticultural-substrate assay at 500 mg L −1 showed higher observed emergence, hypocotyl length, and estimated cotyledon area than the untreated control. These results link SBHH valorization to production of a functionally active crude bioemulsifier and support further evaluation under independently replicated greenhouse or controlled-environment conditions.