Burkholderia thailandensis E264 as a promising safe rhamnolipids\u2019 producer towards a sustainable valorization of grape marcs and olive mill pomace

Alif Chebbi,Andrea Franzetti,Cristiana Rizzi,Sara Villa,Mentore Vaccari,Franco Hernan Gomez Tovar,Silvia Sbaffoni,Massimiliano Tazzari

doi:10.1007/s00253-021-11292-0

Abstract

Within the circular economy framework, our study aims to assess the rhamnolipid production from winery and olive oil residues as low-cost carbon sources by nonpathogenic strains. After evaluating various agricultural residues from those two sectors, Burkholderia thailandensis E264 was found to use the raw soluble fraction of nonfermented (white) grape marcs (NF), as the sole carbon and energy source, and simultaneously, reducing the surface tension to around 35 mN/m. Interestingly, this strain showed a rhamnolipid production up to 1070 mg/L (13.37 mg/g of NF), with a higher purity, on those grape marcs, predominately Rha-Rha C14-C14, in MSM medium. On olive oil residues, the rhamnolipid yield of using olive mill pomace (OMP) at 2% (w/v) was around 300 mg/L (15 mg/g of OMP) with a similar CMC of 500 mg/L. To the best of our knowledge, our study indicated for the first time that a nonpathogenic bacterium is able to produce long-chain rhamnolipids in MSM medium supplemented with winery residues, as sole carbon and energy source.Key points• Winery and olive oil residues are used for producing long-chain rhamnolipids (RLs).• Both higher RL yields and purity were obtained on nonfermented grape marcs as substrates.• Long-chain RLs revealed stabilities over a wide range of pH, temperatures, and salinities

Highlights

The European Commission adopted an ambitious Circular Economy Action Plan in 2015 that covers the whole life cycle of a product: from production and consumption to waste management and the secondary materials market (Grimm and Wösten 2018; Kapoor et al 2020)
Our study aims to assess the rhamnolipid production from winery and olive oil residues as low-cost carbon sources by nonpathogenic strains
Our results indicated that the strain B. thailandensis E264 was a good candidate for further fermentation attempts on the winery wastes (Fig. 1)

Summary

Introduction

The European Commission adopted an ambitious Circular Economy Action Plan in 2015 that covers the whole life cycle of a product: from production and consumption to waste management and the secondary materials market (Grimm and Wösten 2018; Kapoor et al 2020). The development of a CE concept requires adopting closed-loop systems, facilitating the transformation from a linear economy to a CE to improve economic and environmental sustainability (Dessie et al 2020; Kaszycki et al 2020). This model can be especially important in Italy, where agriculture is one of the most productive sectors and, at the same time, responsible for generating large amounts of residues with different proprieties (Vahidzadeh et al 2021). In Italy, more than 8.6 million tonnes of wine grapes were harvested in 2018 from

Methods

Results

Conclusion