By-products of sugar factories and wineries as feedstocks for erythritol generation

Abstract

Erythritol is a polyol suitable for human nutrition which is industrially produced by microorganisms from costly glucose-rich or starch-rich feedstocks. The utilization of sugary by-products from food industries could significantly reduce the costs of the process. Erythritol production from sugarcane molasses, beet molasses and surplus grape musts was assessed, by comparing four fungal strains. Beet molasses presented toxic effects on microorganisms, which hampered erythritol production to a certain extent. Moniliella pollinis attained erythritol production yields of 0.239 ± 0.001 g/g for sugarcane molasses (106.40 ± 0.42 g/L erythritol), 0.229 ± 0.003 g/g for beet molasses (57.78 ± 1.52 g/L), 0.362 ± 0.005 g/g for red grape must (96.26 ± 1.31 g/L) and 0.383 ± 0.004 g/g for rosé grape must (92.84 ± 0.98 g/L), with nearly total sugar consumption in 6-9 days. In comparison, control fermentations with beet syrup reached erythritol yields of 0.327 ± 0.009 g/g (126.78 ± 3.21 g/L). Therefore, erythritol production could be considered as a viable route in certain food industries aiming at market diversification.

From the culture broth to the erythritol crystals: an opportunity for circular economy

“…Summarizing, for the commercial carbon sources, erythritol yields of 0.1–0.6 g/g glucose, 0.26 g/g xylose and 0.66 g/g glycerol were reported (Table 1 ). These values are close to the maximum theoretical erythritol yields of 0.678 g/g hexoses and 0.884 g/g glycerol (Hijosa-Valsero et al 2021 ). Even though glucose and glycerol provide a high selectivity for erythritol production, their high price and volatilities (approx.…”

“…Several studies have assessed different carbon sources for their impact on erythritol to by-product formation by commonly used erythritol-producing microorganisms. This review distinguishes between the usage of purified, commercially available carbon sources such as glucose, xylose (Sasman et al 2007 ; Guo et al 2016 ) or glycerol (Rzechonek et al 2018 ; Rakicka-Pustułka et al 2020 ) and non-conventional substrates, which provide next to a carbon source other nutrients, such as lignocellulosic hydrolysates (Guo et al 2016 ), molasses (Mirończuk et al 2015 ), crude glycerol (Mirończuk et al 2014 ) or residual grape (Hijosa-Valsero et al 2021 ). Obtained erythritol yields and by-product formation as well as the process parameters are given for the most commonly used production organisms in Table 1 (for the conventional carbon sources) and Table 2 (for the non-conventional substrates).…”

“… N.R. YE <5 Hijosa-Valsero et al ( 2021 ) Fructose 150 13.4 Crude glycerol Monilliela megachilensis B 200 100 30 0.17 0.15 N.R. N.R.…”

“…They detected an incomplete sugar consumption with remaining xylose, arabinose and glucose concentrations of 58.0%, 20.2% and 84.8%, respectively, and a final erythritol concentration that was only 17% lower than the control using glucose (Guo et al 2016 ). The evaluation of alternative substrates for erythritol production also included the usage of molasses (Mirończuk et al 2015 ) and fungal-pretreated soybean residues (Liu et al 2017 ) for cultivation of Y. lipolytica , corncob hydrolysate for cultivation of A. pullulans (Guo et al 2016 ), sugarcane molasses, beet molasses, rosé and red grape must for cultivation of M. pollinis (Hijosa-Valsero et al 2021 ) and wheat straw for cultivation of Trichoderma reesei (Jovanović et al 2014 ). Studies on emerging microorganisms for erythritol production included the latter fungus (Jovanović et al 2014 ; Regnat et al 2018 ).…”

“…Concerning erythritol production, research strategies have been implemented such as the use of alternative carbon sources, a further development of production strains, the identification of alternative erythritol-producing microorganisms or the minimization of by-product formation through metabolic engineering (Koh et al 2003 ; Jeya et al 2009 ; Savergave et al 2011 ; Ghezelbash et al 2014 ; Guo et al 2016 ; Regnat et al 2018 ; Liu et al 2019 ; Liu et al 2019 ; Martău et al 2020 ; Hijosa-Valsero et al 2021 ). Despite the progress reported in many studies on the upstream and cultivation stage, there is limited information about optimization strategies of the downstream part.…”