Graphene coated magnetic nanoparticles facilitate the release of biofuels and oleochemicals from yeast cell factories

Santosh Pandit,Ivan Mijakovic,Vrss Mokkapati,Oliver Konzock,Alessandra Merlo,Jie Sun,Kirsten Leistner

doi:10.1038/s41598-021-00189-7

Abstract

Engineering of microbial cells to produce high value chemicals is rapidly advancing. Yeast, bacteria and microalgae are being used to produce high value chemicals by utilizing widely available carbon sources. However, current extraction processes of many high value products from these cells are time- and labor-consuming and require toxic chemicals. This makes the extraction processes detrimental to the environment and not economically feasible. Hence, there is a demand for the development of simple, effective, and environmentally friendly method for the extraction of high value chemicals from these cell factories. Herein, we hypothesized that atomically thin edges of graphene having ability to interact with hydrophobic materials, could be used to extract high value lipids from cell factories. To achieve this, array of axially oriented graphene was deposited on iron nanoparticles. These coated nanoparticles were used to facilitate the release of intracellular lipids from Yarrowia lipolytica cells. Our treatment process can be integrated with the growth procedure and achieved the release of 50% of total cellular lipids from Y. lipolytica cells. Based on this result, we propose that nanoparticles coated with axially oriented graphene could pave efficient, environmentally friendly, and cost-effective way to release intracellular lipids from yeast cell factories.

Highlights

Engineering of microbial cells to produce high value chemicals is rapidly advancing
To more closely examine the morphology of Y. lipolytica cells exposed to graphene-coated nanoparticles, we further examined them by SEM (Fig. 5)
Our results demonstrate that nanoparticles that are coated with sharp graphene spikes can be used to effectively break the cells and release intracellular lipids from Y. lipolytica (Fig. 4)

Summary

Introduction

Engineering of microbial cells to produce high value chemicals is rapidly advancing. Yeast, bacteria and microalgae are being used to produce high value chemicals by utilizing widely available carbon sources. We hypothesized that the exposed sharp edges of graphene spikes, deposited axially on magnetic nanoparticles, could interact with the membranes of yeast cells and thereby facilitate the release of valuable lipids (biofuels and oleochemicals) produced by these cell factories. To test this hypothesis, we decided to work with a strain of Y. lipolytica that has been genetically engineered for high-level production of lipids[26]. For displacement of lipids from the membrane onto the graphene surface, the optimal contact angle between the graphene sheet and the biological membrane surface is 90o15–18

Methods

Results

Conclusion