Non-edible biomass as innovative substrate for lipid biosynthesis: a step towards circular economy

In the realm of food security, there is growing recognition of lignocellulosic biomass as a valuable resource for meeting various food production needs. To advance the design of efficient processes for converting biomass into food-related value-added products, it is vital to gain a deep understanding of its distinctive properties. This research study was conducted for extensive physico-chemical analysis of non-edible and waste lignocellulosic biomass sources, all with the overarching objective of enhancing their utilization as potential feedstock in biolipid production. The present study revealed that both apricot kernel shell (AKS) and almond green husk (AGH) have high polysaccharides and low lignin content. FTIR spectra showed the existence of functional groups attributed to cellulose, hemicellulose, and lignin. The weight loss of 51.32% and 57.17% in AKS and AGH, respectively, was observed in the temperature range of 250 to 400 °C. Calorimetry analysis found that hemicellulose was relatively more thermally stable than cellulose. AKS has a lower crystallinity index (66.6%) compared to AGH (70.1%). The compositional as well as SEM/EDX analysis supports the suitability of AKS as a potential feedstock for microbial lipid production than AGH. Furthermore, flow behavior patterns showed a sharp decline in viscosity at solid loading from 10–14%. The present study could significantly advance knowledge of the possible uses of AKS and AGH for the techno-economic viability of biomass produced as food waste or byproduct.