High level xylitol production by Pichia fermentans using non-detoxified xylose-rich sugarcane bagasse and olive pits hydrolysates

Vivek Narisetty,Eulogio Castro,Sumit Durgapal,Frederic Coulon,Samuel Jacob,Dinesh Kumar,Mukesh Kumar Awasthi,Kamal Kishore Pant,Binod Parameswaran,Vinod Kumar

doi:10.1016/j.biortech.2021.126005

Abstract

Hemicellulosic sugars, the overlooked fraction of lignocellulosic residues can serve as potential and cost-effective raw material that can be exploited for xylitol production. Xylitol is a top platform chemical with applications in food and pharmaceutical industries. Sugarcane bagasse (SCB) and olive pits (OP) are the major waste streams from sugar and olive oil industries, respectively. The current study evaluated the potential of Pichia fermentans for manufacturing of xylitol from SCB and OP hydrolysates through co-fermentation strategy. The highest xylitol accumulation was noticed with a glucose and xylose ratio of 1:10 followed by feeding with xylose alone. The fed-batch cultivation using pure xylose, SCB, and OP hydrolysates, resulted in xylitol accumulation of 102.5, 86.6 and 71.9 g/L with conversion yield of 0.78, 0.75 and 0.74 g/g, respectively. The non-pathogenic behaviour and ability to accumulate high xylitol levels from agro-industrial residues demonstrates the potential of P. fermentans as microbial cell factory.

Highlights

Sugar is an inextricable part of the diet, but the excessive con sumption leads to obesity, type II diabetes, and other cardiovascular disorders
We have shown the potential of P. fermentans to manufacture xylitol from pure and xylose-rich crude agricultural residues (Prabhu et al, 2020a)
The results shows that presence of glucose in the fermen tation medium is beneficial for boosting up the xylitol accumulation

Summary

Introduction

Sugar is an inextricable part of the diet, but the excessive con sumption leads to obesity, type II diabetes, and other cardiovascular disorders. As excessive consumption has negative impact on the health, the medical professionals recommend the non-nutritive or non-sugar sweeteners. Xylitol has several health benefits due to its low energy content and anticarcinogenic properties and can be used in treatment of various dis eases like diabetes, colon diseases, haemolytic anaemia, respiratory in fections, osteoporosis, iron deficiency, cystic fibrosis, and other pathological disorders (Lopez-Linares et al, 2018; Tiwari and Baghela, 2020). Owing to its inherent nutritional value, and unprecedented de mand from various sectors, the global xylitol market exceeded $880 million in 2019, and is expected to grow up to $1.37 billion by 2025 with a Compound Annual growth Rate (CAGR) of 6.6%. Ltd.; Novagreen Inc.; Roquette Freres; S2G Biochem; Xylitol Canada, Inc.; Zuchem Inc., and others Xylitol Market Size Worth $1.37 Billion By 2025 | Growth Rate: 6.6% (grand viewresearch.com) (Accessed 22nd September 2021)

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Conclusion