Simultaneous lipid biosynthesis and recovery for oleaginous yeast Yarrowia lipolytica

Abstract

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 (Heff/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.

Harnessing pongamia shell hydrolysate for triacylglycerol agglomeration by novel oleaginous yeast Rhodotorula pacifica INDKK

“…The data elucidate that R. pacifica INDKK was tolerant to pre-treatment-generated inhibitors with potential to utilize different carbon sources present in lignocellulosic hydrolysates. The results were consistent with previously reported literature, wherein yeast such as Trichosporon fermentans and Cryptococcus curvatus were reported with similar potential but with low lipid productivity [6,33].…”

“…Hence, we optimized microwave-aided Nile red staining for yeast generating emission peak at ~ 580 nm and clearly differentiating the Rhodosporidium dibovatum (NCIM-3658) showed higher or comparable RFU value ( Fig. 2a) to Yarrowia lipolytica (NCIM-3590), a previously reported high lipidaccumulating yeast isolate [33]. The high lipid accumulation in these isolates was further confirmed by lipid droplet (LD) size measurement using confocal microscopy (Additional file 3: Figure S2).…”

Alpha-Ketoglutaric Acid Production from a Mixture of Glycerol and Rapeseed Oil by Yarrowia lipolytica Using Different Substrate Feeding Strategies

“…Definitely, the best results were obtained by these authors in the repeated fed-batch process, which allowed them to indicate this process as applicable on the industrial scale. The repeated batch culture was also used for citric acid production by Y. lipolytica from inulin [37] and glycerol [38], for erythritol biosynthesis from glycerol [39], or for the production of lipid-rich biomass of Y. lipolytica yeast [40]. In the present study, we used a wild yeast strain Y. lipolytica A-8, isolated in 1974 from the soil around a car repair shop in Wrocław, Poland.…”

Extractive production of microbial oil using hydrophobic adsorbents: A comparative study

“…The hydrophobic adsorbents were introduced into the oil production broth at the onset (0 hour) of the fermentation to achieve a concurrent production and a simultaneous in situ oil capture inside the broth. 17 Initial studies at shake flask level were carried out by adding 1 g of adsorbent resins to the oil production medium along with the inoculation of cell biomass obtained from the growth phase cells. The in situ oil recovery using adsorbent resins was also studied microscopically to visualize the phenomenon of oil capture.…”

“…These surface lipids were observed to affect the flux across the cell membrane and also the substrate uptake kinetics. 17 Negative feedback elicited by these lipids also inhibits the biosynthesis of microbial oil inside the cells and regulates cellular homeostasis. 23 Thus, it becomes important to stall this extracellular oil saturation in the aqueous phase as well as on the cell surface.…”