Cost-Effective Cultivation of Native PGPB Sinorhizobium Strains in a Homemade Bioreactor for Enhanced Plant Growth

Luis Alberto Manzano-Gómez; Reiner Rincón-Rosales; José David Flores-Felix; Adriana Gen-Jimenez; Víctor Manuel Ruíz-Valdiviezo; Lucia María Cristina Ventura-Canseco; Francisco Alexander Rincón-Molina; Juan José Villalobos-Maldonado; Clara Ivette Rincón-Molina

doi:10.3390/bioengineering10080960

Cost-Effective Cultivation of Native PGPB Sinorhizobium Strains in a Homemade Bioreactor for Enhanced Plant Growth

Bioengineering (Basel). 2023 Aug 13;10(8):960. doi: 10.3390/bioengineering10080960.

Authors

Luis Alberto Manzano-Gómez^{1

2}, Reiner Rincón-Rosales¹, José David Flores-Felix³, Adriana Gen-Jimenez¹, Víctor Manuel Ruíz-Valdiviezo¹, Lucia María Cristina Ventura-Canseco¹, Francisco Alexander Rincón-Molina¹, Juan José Villalobos-Maldonado¹, Clara Ivette Rincón-Molina¹

Affiliations

¹ Laboratorio de Ecología Genómica, Tecnológico Nacional de México, Instituto Tecnológico de Tuxtla Gutiérrez, Tuxtla Gutiérrez 29050, Chiapas, Mexico.
² Departamento de Investigación y Desarrollo, 3R Biotec SA de CV, Tuxtla Gutiérrez 29000, Chiapas, Mexico.
³ Departamento de Microbiología y Genética, Universidad de Salamanca, 37007 Salamanca, Spain.

Abstract

The implementation of bioreactor systems for the production of bacterial inoculants as biofertilizers has become very important in recent decades. However, it is essential to know the bacterial growth optimal conditions to optimize the production and efficiency of bioinoculants. The aim of this work was to identify the best nutriment and mixing conditions to improve the specific cell growth rates (µ) of two PGPB (plant growth-promoting bacteria) rhizobial strains at the bioreactor level. For this purpose, the strains Sinorhizobium mexicanum ITTG-R7^T and Sinorhizobium chiapanecum ITTG-S70^T were previously reactivated in a PY-Ca²⁺ (peptone casein, yeast extract, and calcium) culture medium. Afterward, a master cell bank (MCB) was made in order to maintain the viability and quality of the strains. The kinetic characterization of each bacterial strain was carried out in s shaken flask. Then, the effect of the carbon and nitrogen sources and mechanical agitation was evaluated through a factorial design and response surface methodology (RSM) for cell growth optimization, where µ was considered a response variable. The efficiency of biomass production was determined in a homemade bioreactor, taking into account the optimal conditions obtained during the experiment conducted at the shaken flask stage. In order to evaluate the biological quality of the product obtained in the bioreactor, the bacterial strains were inoculated in common bean (Phaseolus vulgaris var. Jamapa) plants under bioclimatic chamber conditions. The maximum cell growth rate in both PGPB strains was obtained using a Y-Ca²⁺ (yeast extract and calcium) medium and stirred at 200 and 300 rpm. Under these growth conditions, the Sinorhizobium strains exhibited a high nitrogen-fixing capacity, which had a significant (p < 0.05) impact on the growth of the test plants. The bioreactor system was found to be an efficient alternative for the large-scale production of PGPB rhizobial bacteria, which are intended for use as biofertilizers in agriculture.

Keywords: PGPB; Sinorhizobium; biofertilizer; bioreactor prototype; cell growth rates.

Abstract

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