Isolation and Molecular Identification of the Native Microflora on Flammulina velutipes Fruiting Bodies and Modeling the Growth of Dominant Microbiota (Lactococcus lactis)

Abstract

The objectives of this study were to isolate and identify the dominant microorganism in Flammulina velutipes fruiting bodies (FVFB) and to develop kinetic models for describing its growth. The native microflora community on FVFB was isolated and identified using morphological examination and high-throughput sequencing analysis. FVFB presented complex microbial communities with dominant microorganisms being Lactococcus lactis. Irradiated FVFB were inoculated with the isolated strain of L. lactis and cultivated at various temperatures (4, 10, 16, 20, 25, 32, and 37°C). Three primary models, namely the Huang, Baranyi and Roberts, and reparameterized Gompertz models, and three secondary models, namely the Huang square-root, Ratkowsky square-root, and Arrhenius-type models, were developed and evaluated. With the lowest values of mean square error (MSE, 0.023–0.161) and root mean square error (RMSE, 0.152–0.401) values, the reparameterized Gompertz model was more suitable to describe the growth of L. lactis on FVFB than both Huang and Baranyi and Roberts models. The Ratkowsky square-root model provided more accurate estimation for the effect of temperature on the specific growth rate of L. lactis. The minimum growth temperature predicted by the Ratkowsky square-root model was −7.1°C. The kinetic models developed in this study could be used to evaluate the growth behavior of L. lactis on FVFB and estimate the shelf-life of FVFB.

Isolation and Identification of Acer truncatum Endophytic Fungus Talaromyces verruculosus and Evaluation of Its Effects on Insoluble Phosphorus Absorption Capacity and Growth of Cucumber Seedlings

“…The PCR amplification system was 25 µL, including 9.5 µL ddH 2 O, 2 µL primers (ITS-1, ITS-4), and 12.5 µL 2 × Taq PCR Master Mix. In total, 1 µL template DNA was amplified with the fungal universal primer ITS-1(5 ′ -TCCGTAGGTGAACCTGCGG-3 ′ )ITS-4(5 ′ -TCCTCCGCTTATTGATATGC-3 ′ ), and the reaction conditions were as follows: predenaturation at 94 C for 5 min [32]. The PCR products were identified by 1% agarose gel electrophoresis, and the PCR products were sent to Beijing Liuhe BGI Gene Technology Co., Ltd. (Beijing, China) for sequencing.…”