STUDIES ON PRODUCTION OF VALUE-ADDED PRODUCTS FROM ALOE VERA LEAF RIND HYDROLYSATE USING Rhodosporidium toruloides 3547

Abstract

The requirement to construct on the demand for sustainable components in second generation bio-refineries can only be fulfilled through modern and environment friendly technologies based on bioprocess mechanisms such as organosolv treatment, transesterification, and various catalytic procedures to make more composite molecules and matter on which a future durable society can be built. Aloe vera leaf rind (AVLR), a waste biomass has no commercial usage and could provide as an efficient lignocellulosic feedstock for bio-based product manufacturing where the requisite is a viable pretreatment to separate cellulose, hemicellulose and lignin into different streams. The use of unconventional oleaginous yeast Rhodosporidium toruloides 3547 to produce value added products using agro-waste like aloe vera leaf rind (a lignocellulosic waste) liquid hydrolysate as the sole carbon source has been hypothesized in this project work which has not been tried so far. Here, AVLR is characterized for compositional analysis and components such as protein (2195.64 mg/l), cellulose (2022.58 mg/l), hemicellulose (993.54 mg/l), total carbohydrates (1693.53 mg/l), and lignin (7.75%) etc, are observed which show a promising probability towards further by-product production. Organosolv method can be utilized to attain pure lignin with less than 1% weight of residual carbohydrate quantity. In this study, various catalyst compositions such as FeCl3 hydrolysate (4 fold increase in reducing sugars), CuCl hydrolysate (3 fold increase in reducing sugars), etc, are analyzed for efficiency and microbial growth profiling as the pretreatment using the organosolv method. “CuCl hydrolysate with yeast basal media” catalyst is found to have the highest sugar consumption rate (94%), thereby showing the highest sugar uptake rate (11.33 mg h-1 ) and maximum biomass production (95 mg/hour at optimal growth). Qualitative and quantitative analysis of intracellular lipids through techniques such as staining, FTIR, GC-MS and XRD has also provided favorable results in the samples obtained. The qualitative analysis using Sudan Black stain revealed that the” CuCl hydrolysate” catalyst treated sample accumulated maximum lipid while “FeCl3 hydrolysate” catalyst accumulated the least. In quantitative analysis “Cu v Cl hydrolysate” catalyst treated sample is found to have the highest lipid content (48%), due to its higher efficiency in fractionalization of the components. Fourier-Transform Infra-Red (FTIR) spectra released peak at about 1732 cm-1 , with the inference that in “CuCl hydrolysate” catalyst treated AVLR, the hemicellulose is extracted fully but not in “FeCl3 hydrolysate” treatment. The presence of peaks near the region 1600 cm-1 and 1423 cm-1 indicates the presence of lignin in both raw and pre-treated AVLR and these peaks correspond to the phenyl and methyl propane groups present in the lignin. This study found that the organosolv pretreatment of AVLR biomass can efficiently enhance the yield of fermentable sugars and lipid production which can be further utilized for by-product manufacturing such as biofuels, carotenoids, etc.