Porungo cheese whey: β-galactosidase production, characterization and lactose hydrolysis

Marco Antônio Záchia Ayub,Aline Vitória Corim Marim,Sabrina Gabardo

doi:10.1590/1981-6723.03821

Marco Antônio Záchia Ayub, Aline Vitória Corim Marim + Show 1 more

Open Access

https://doi.org/10.1590/1981-6723.03821

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Abstract

Abstract This study evaluated the lactose hydrolysis by immobilized β-galactosidase, which was produced by Kluyveromyces marxianus using porungo cheese whey as substrate. Initially, the yeast was cultivated in porungo cheese medium at 30 °C and 200 rpm, showing a maximal β-galactosidase production of 14.19 U mL-1. The crude extract obtained was used to evaluate the enzymatic hydrolysis in lactose solution. The optimal pH and temperature of the free and immobilized enzyme was investigated, whereas the lactose hydrolysis was carried out using two enzyme solutions (total activities of 2 U and 6 U) for both forms of the biocatalyst. Ca-alginate immobilization of β-galactosidase increased optimal temperature range to 40 °C, compared to the value for the free enzyme, which was 37 °C. The optimal pH was also increased by immobilization to 7.0, from pH 6.5 observed for the free enzyme. The highest lactose hydrolysis conversion was 15.82% using 6 U of free enzyme and 13.77% for 2 U of immobilized enzyme. Although, free enzyme showed higher conversion rates in the initial reaction time, the immobilized enzyme kept operational stability throughout reaction time, suggesting the advantage of using this technology. The use of porungo cheese whey allowed to aggregate value to this agro-industrial by-product, with the concomitant production of β-galactosidase to be used in the food industry chain itself.

Highlights

The use of agro-industrial by-products or residues, such as cheese whey, as cheap and alternative substrates in biotechnological processes have been widely researched to obtain added-values biomolecules and has encouraged development of new strategies in bioprocess technology (Christensen et al, 2011; Gabardo et al, 2016)
Due to its nutrient composition, rich in lactose (45-50 g L-1), protein (6-8 g L-1), lipids (4-5 g L-1), and mineral salts (5-7 g L-1), the remaining volume of the cheese whey have a potential to be applied in bioprocess as substrate for microbial growth to obtain several biomolecules, especially enzymes such as β-galactosidase, serving as alternative carbon low-cost to production of food industry (Siso, 1996; Guimarães et al, 2010; Prazeres et al, 2012; Domingos et al, 2018; Coelho et al, 2021; Bolognesi et al, 2021)
This study aimed to investigate the lactose enzymatic hydrolysis by β- galactosidase produced in porungo cheese whey medium in fermentations of K. marxianus

Summary

Introduction

The use of agro-industrial by-products or residues, such as cheese whey, as cheap and alternative substrates in biotechnological processes have been widely researched to obtain added-values biomolecules and has encouraged development of new strategies in bioprocess technology (Christensen et al, 2011; Gabardo et al, 2016). Porungo cheese is manufactured by farmers using raw milk and has similar characteristics of mozzarella cheese, being produced in the southwestern region of São Paulo State, in Brazil. It naturally contains a large number of lactic bacteria prevenient from fermented whey of the previous cheese production (Pezzo, 2017; Coelho et al, 2021; Bolognesi et al, 2021). Our research groups are a pioneer group to investigate the biotransformation of porungo cheese whey in bioprocess

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