Enhanced Glucan–Chitin\nComplex Extraction from\nDeoiled Yeast Biomass for Sustainable Biorefinery Applications

Spent microbial biomass is a major type of carbon and\nnitrogen-rich\nby-product generated by bioprocess industries. These spent biomasses,\nrich in valuable carbohydrates, has remained underutilized due to\na limited understanding of their conversion to value products. One\nsuch solid by-product stream is carbohydrate-rich (64.56 wt %) de-oiled\nyeast biomass, a type of spent microbial biomass originating from\nthe oleaginous fermentation process. The present study deals with\nthe enrichment and extraction of the glucan–chitin complex\nfrom DYB focusing on scalability with minimal release of chemical\nload to the environment. The complex obtained through sequential fractionation\nand hypochlorite-assisted extraction was assessed for its quality\nand structural characteristics. A glucan–chitin complex enrichment\nfrom 4 to 49.22 wt % glucan with a 17.07 wt % chitin was obtained,\nexhibiting a helical arrangement of β-(1 → 3) and β-(1\n→ 6) glucan chains linked to chitin via β-(1 →\n4) linkage. The results showed that the investigated process could\nbe integrated with the yeast lipid production chain to obtain these\nquality compounds from its by-product stream. The green chemistry\nmetrics, viz., PMI, atom economy, and optimum efficiency of 23.34\nkg/kg, 1.41, and 8.36, indicated the need for recovery of compounds\nfrom the secondary discharge stream of the investigated method to\nfurther minimize the carbon and nitrogen loss as a resource.