High-Efficiency Production of Auricularia polytricha Polysaccharides Through Yellow Slurry Water Fermentation and Its Structure and Antioxidant Properties.

Zhengbin Yang,Xuefeng Zeng,Laping He,Wei Zhang,Furong Zhang,Jingui Liu,Hongya Ao,Jiangli Wu,Yuedan Hu,Yong Zhu

doi:10.3389/fmicb.2022.811275

Abstract

Yellow slurry water is a kind of nutrient-rich wastewater of tofu. Firstly, the medium of yellow slurry was optimized. Then, APP40, APP60, and APP80 were obtained by sedimentation with different concentration of ethanol (40, 60, and 80%). The physicochemical properties and primary structures of the three polysaccharides were studied by high performance anion exchange chromatography (HPAEC), high performance gel filtration chromatography (HPGFC), scanning electron microscope (SEM), atomic force microscope (AFM), and Fourier transform infrared (FT-IR) spectrometer. Finally, the effects of three polysaccharides on antioxidation activity were studied. According to the experimental optimization the results, the biomass and the production of Auricularia polytricha Polysaccharides (APPS) reached the peak, and they were 13.5 ± .655 and 9.42 ± .253 g/L (p < .05). The SEM and the AFM showed that the height of APP80 gradually increased from 31.1 to 46.7 nm and from APP40 to APP80. The particle size of APP80 increased, the pores decrease or even disappear, and the molecules begin to aggregate. The FT-IR spectrum analysis showed that the three polysaccharides possessed key functional groups. The carbohydrate content of APP40, APP60, and APP80 was 20.2, 34.25, and 31.73%. The molecular weights of APP40, APP60, and APP80 are 9.462 × 104, 8.742 × 104, and 8.091 × 104 Da, respectively. The three polysaccharides were composed of rhamnose, galactose, glucose, mannose, and xylose but with different molar ratio. APP80 showed strong reducing ability and scavenging activity of 2,2–diphenyl–1–picrylhydrazyl (DPPH) and hydroxyl radicals through antioxidant activities evaluated in vitro. This study introduces a way for the effective use of yellow slurry water.

Highlights

Yellow slurry water is high nutrition by–product in tofu processing (Wang and Serventi, 2019)
Auricularia polytricha-10 was placed in the fermentation bottle for fermentation for 3 days
The results demonstrated that the crystal structure of Auricularia polytricha Polysaccharides (APPS) was slightly damaged after 40% ethanol precipitation

Summary

Introduction

Yellow slurry water is high nutrition by–product in tofu processing (Wang and Serventi, 2019). It is reported that the general solid content of yellow slurry water is as high as 1%, of which protein (.4%–.5%), total sugar (1%–2%), and a variety of vitamins, organic acids, amino acids, lipids, and other organic components are in line with the nutritional environment required by the growth of multifaceted microorganisms (Guldhe et al, 2017). Some efforts have been made to utilize yellow slurry water as the medium to produce various products. Yellow slurry water has been found suitable for the growth of edible fungi, such as Tremella aurantialba and Hericium erinaceus (Zhang et al, 2014; Sun et al, 2020), and can lead to higher productivities of polysaccharides

Methods

Results

Conclusion