Improvement of Sporulation Conditions of a New Strain of <i>Bacillus amyloliquefaciens</i> in Liquid Fermentation

Abstract

The desirable active ingredients for the development of bioproducts based in Bacillus sp. for the control of soil pathogens are the spores because these structures exhibit more resistance and stability to conditions present during the fermentation, formulation, and storage processes. To improve the sporulation of a native strain of Bacillus amyloliquefaciens (Bs006) using liquid fermentation, some modifications in the concentrations of the components in a previously standardized culture media were made. Subsequently, five sporulation inducers (iron nitrate, mixture of salts, peroxide hydrogen, temperature, and initial cell concentration) were evaluated. The treatment with a mixture of salts in combination with an initial cell concentration of 1 × 10 8 cells/ml was selected because a final spore concentration of 1.05 × 10 10 spores/ml after 66 hours with a fully substrate consumption and sporulation efficiency of 88.7% was obtained. To demonstrate the biological activity of B. amyloliquefaciens Bs006 in Cape gooseberry seedlings, a greenhouse bioassay was conducted, and statistical differences in plant growth-promoting parameters compared with previous media were not found. Additionally, the proposed modified media (coded as JM) presented a benefit-cost ratio 2.65 times higher compared with the baseline media.

Control de Sclerotium cepivorum y promoción del crecimiento en ajo (Allium sativum) con microorganismos antagonistas

“…Respecto a la promoción de crecimiento vegetal, aún en presencia del patógeno, se observaron para las variables evaluadas comportamientos similares o mejores con respecto al control, para los tratamientos que incluyeron a T. koningiopsis cepa Th003 y B. amyloliquefaciens cepa Bs006. La capacidad de B. amyloliquefaciens cepa Bs006 para colonizar el sistema radicular de ajo (dato no mostrado), permitió evidenciar un efecto sobre el crecimiento, el cual podría estar mediado por la producción de hormonas como el ácido indol-3-acético (IAA) y las giberelinas (Díaz-García et al, 2015;Gámez et al, 2018;Zapata & Díaz, 2012).…”

“…Los bioplaguicidas utilizados fueron Tricotec® WG (granulo dispersable) a base de conidios de Trichoderma koningiopsis cepa Th003 y dos prototipos de bioplaguicida, uno WG a base de conidios de Trichoderma asperellum cepa Th034 y otro líquido a base de esporas de Bacillus amyloliquefaciens cepa Bs006, desarrollados por la Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA) (Díaz-García et al, 2015;Santos et al, 2012). Se realizaron tres mezclas entre los bioplaguicidas (Th003 + Th034; Th003 + Bs006 y Th034 + Bs006); la concentración de uso fue de 1x10 6 conidios/mL para los hongos y 1x10 8 esporas/mL para la bacteria, aplicados de forma individual o en mezclas.…”

Enhancement of drought tolerance on guinea grass by dry alginate macrobeads as inoculant of Bacillus strains

“…The strains were reactivated in trypticase soy agar culture medium (TSA, Difco Laboratories, Detroit, MI, USA) at standard conditions: 30 °C for 24 h. Bacterial pre-inoculum was produced aerobically by growing each strain in the log phase at standard conditions subjected to shaking at 150 rpm, cultivating the cells in JM broth (Díaz-García et al 2015). Then, for spore preparation, we carried out a fermentation process using the pre-inoculum produced in a Rushton (Miniforms, INF-30174, Bottmingen, CH) type turbine-agitated fermenter (capacity 5 L) at 150 rpm, 30 °C with 1 vvm and an effective volume of 3.5 L. At 72 h, a spore concentration of 1.05 × 10 10 spore mL −1 was obtained from each one of the strains that were calculated by making serial dilutions; the count was made using Neubauer chamber (BOECO, DE).…”

Efficacy of microbial antagonists and chitin in the control of Colletotrichum gloeosporioides in postharvest of mango cv. Azúcar

“…Efficacy of antagonistic microorganisms in the control of anthracnose. The AGROSAVIA Microorganism Germplasm Bank provided the antagonistic microorganisms characterized in previous studies and which displayed control over different pathogens (Zapata and Cotes, 2013;Díaz-García et al, 2015), which were the bacteria Bacillus amyloliquefaciens Bs006 (Gámez et al, Fully Bilingual Revista Mexicana de FITOPATOLOGÍA Mexican Journal of Phytopathology gloeosporioides), proveniente de frutos de mango variedad Yulima, identificado por su morfología y seleccionado por su patogenicidad al realizar los postulados de Koch (datos no mostrados). Su inoculo se obtuvo a partir de conidios colectados de cultivos en Agar Papa Dextrosa (PDA, Oxoid ® ) incubados a 25 °C durante 10 días, a partir de los cuales se realizó una suspensión de 1x10 5 conidios mL -1 en agua destilada estéril.…”

“…Eficacia de microorganismos antagonistas en el control de la antracnosis. El Banco de Germoplasma de Microorganismos de AGROSAVIA proporcionó los microorganismos antagonistas que en estudios previos se caracterizaron y mostraron control sobre diferentes patógenos (Zapata y Cotes, 2013;Díaz-García et al, 2015), los cuales correspondieron a las bacterias Bacillus amyloliquefaciens Bs006 (Gámez et al, 2015), Bacillus safensis AP280 y Lysinibacillus xylaniticus AP282; y las levaduras Candida oleophila Lv037, Pichia onychis Lv297 y Rhodotorula glutinis Lv316 (Moreno et al, 2012;Zapata et al, 2011). Para su crecimiento, las bacterias fueron cultivadas en caldo Luria Bertani (LB, Oxoid ® ) y las levaduras en caldo extracto de malta y levadura (YM, Oxoid ® ) a 125 rpm, 28 °C durante 48 y 72 horas respectivamente.…”