Modeling and Regulation of Higher Alcohol Production through the Combined Effects of the C/N Ratio and Microbial Interaction

Abstract

Too large of a higher alcohol content has negative effects on the liquor taste and health. Revealing the key microbes and their key driving forces is essential to regulate the higher alcohol content in spontaneous liquor fermentation. Herein, we used high-throughput sequencing associated with a multivariate statistical algorithm to reveal the contributing microbes for higher alcohol production in Chinese light-aroma-type liquor and identified that Saccharomyces and Pichia were the main contributors. In addition, the C/N ratio and microbial interaction were found to significantly affect the production of higher alcohols. Herein, we used response surface methodology to establish a predictive model for higher alcohol production with the regulating factors, and the content of total higher alcohols decreased significantly from 328.80 ± 24.83 to 114.88 ± 5.02 mg/L with the optimized levels of the regulators. This work would facilitate the control of flavor production via regulating microbial communities in food fermentation.

Microbial Community Succession and Its Environment Driving Factors During Initial Fermentation of Maotai-Flavor Baijiu

“…The acidity was measured based on the methods described by others (Tan et al, 2019). Alcohol, reducing sugar, and organic acids were analyzed via high-performance liquid chromatography (HPLC; Waters 2,695, Milford, United States) equipped with refractive index detector (RID, 2414) and photodiode array detector (PDA, 2998), based on the method described elsewhere (Zheng et al, 2014b;Wang et al, 2017;Jiang et al, 2019).…”

Profiling the effects of physicochemical indexes on the microbial diversity and its aroma substances in pit mud

“…Besides, it can guide us to build a combination with predictive models to increase or decrease the content of a certain flavour substance (Jiang et al . 2019). Therefore, this research may help us improve our understanding of Baijiu aroma characteristics and provide a theoretical basis for better regulation of Baijiu quality.…”

“…In the pits, we can adjust some basic physicochemical indexes, such as moisture content and pH, to make the surrounding environment more conducive to the survival of micro-organisms that can produce beneficial flavour substances, thereby increasing the production of flavour substances such as ethyl hexanoate and ethyl octanoate. Besides, it can guide us to build a combination with predictive models to increase or decrease the content of a certain flavour substance (Jiang et al 2019). Therefore, this research may help us improve our understanding of Baijiu aroma characteristics and provide a theoretical basis for better regulation of Baijiu quality.…”

Gradient Internal Standard Method for Absolute Quantification of Microbial Amplicon Sequencing Data

“…The qPCR was performed on a real-time PCR system (Applied Biosystems, Foster City, CA) with a mixture of 0.4 ml (20 mM) of primers, 10.0 ml of SYBR green supermix (SYBR Premix Ex Taq II; TaKaRa, Shanghai, China), 1.0 ml of DNA templates, and 8.2 ml of double-distilled water (ddH 2 O) (38). The PCR program was as follows: preheating at 98°C for 10 min, 40 cycles at 98°C for 30 s and 60°C for 30 s, and an increase of 0.5°C every 5 s from 72°C to 95°C for the melting-curve analysis to confirm the amplification specificity (39).…”