Pratik Prashant Pawar

Over the years, human lifestyle and food habits have changed drastically. This current century has also seen an increased awareness about personal well-being, raising consumer demands for obtaining functional ingredients in concentrated forms to meet nutrient requirements and combat diseases. The hunt for these ‘nutraceuticals’ has triggered exploratory research for obtaining such natural bioactive compounds. While there has been a significant advancement in obtaining bioactives from microbial and animal sources, they face severe apprehensions on ethical grounds. Moreover, the product titres obtained from these routes are considerably lower and fail to suffice as a reliable resource. Therefore, it becomes inevitable to unleash the underutilized potential of agro-food wastes, which is rich in various bioactive compounds, like lipids, proteins, fibres, flavonoids, phytochemicals, etc. However, these by-products and agro-food wastes are ascribed with complexities and recalcitrant natures owing to the diverse segments which generate them together in enormous amounts every day. These adversities, therefore, challenge their sustainable and complete utilisation. Moreover, the uncertainties associated with the qualitative and quantitative aspects of agro-food wastes also limit their applicability. This chapter discusses recent advances and possibilities of developing selective strategies for recovery, encapsulation, and applying nutraceuticals derived from agro-food wastes.

Increased demand for vegetable oils has accelerated interest in producing its renewable alternate through microbial route. However, this process still awaits technological advancements to be executed as a commercially feasible operation. The oil productivity in this bioprocess is significantly challenged by the conventional recovery techniques used. To address this problem, we propose an extractive production system using hydrophobic adsorbents as oil capturing agents for simultaneous in situ oil recovery. Three polystyrene and two organo‐silica‐based capturing agents were studied on a “cell mimic system” to attest to an increase in the rate of oil recovery. High sorption capacity demonstrated by SEPABEADS, stalled the oil saturation in the aqueous medium and thereby, enhances the extracellular efflux of the produced oil. The efflux of oil, when matched with the substrate assimilation, allows for an increased production rate of oil. As a result, we observe and report oil production to 80% dry cell weight and volumetric productivity of 0.11 g L⁻¹ hour⁻¹. With SEPABEADS SP70 as an in situ oil capturing agent in the broth, the wild type “Yarrowia lipolytica” cells yield 0.33 g_oil g⁻¹_glucose, allowing us to propose a highly efficient system for extractive production of microbial oil.

Background: Recent trends in bioprocessing have underlined the significance of lignocellulosic biomass conversions for biofuel production. These conversions demand at least 90% energy upgradation of cellulosic sugars to generate renewable drop-in biofuel precursors (H_eff/C ~ 2). Chemical methods fail to achieve this without substantial loss of carbon; whereas, oleaginous biological systems propose a greener upgradation route by producing oil from sugars with 30% theoretical yields. However, these oleaginous systems cannot compete with the commercial volumes of vegetable oils in terms of overall oil yields and productivities. One of the significant challenges in the commercial exploitation of these microbial oils lies in the inefficient recovery of the produced oil. This issue has been addressed using highly selective oil capturing agents (OCA), which allow a concomitant microbial oil production and in situ oil recovery process.Results: Adsorbent-based oil capturing agents were employed for simultaneous in situ oil recovery in the fermentative production broths.Yarrowia lipolytica, a model oleaginous yeast, was milked incessantly for oil production over 380 h in a media comprising of glucose as a sole carbon and nutrient source. This was achieved by continuous online capture of extracellular oil from the aqueous media and also the cell surface, by fluidizing the fermentation broth over an adsorbent bed of oil capturing agents (OCA). A consistent oil yield of 0.33 g per g of glucose consumed, corresponding to theoretical oil yield over glucose, was achieved using this approach. While the incorporation of the OCA increased the oil content up to 89% with complete substrate consumptions, it also caused an overall process integration.Conclusion: The nondisruptive oil capture mediated by an OCA helped in accomplishing a trade-off between microbial oil production and its recovery. This strategy helped in realizing theoretically efficient sugar-to-oil bioconversions in a continuous production process. The process, therefore, endorses a sustainable production of molecular drop-in equivalents through oleaginous yeasts, representing as an absolute microbial oil factory.