Three soil-compost based carrriers were elaborated and autoclaved by three different treatments of fractionated sterilization in two consecutive days. The efficiency of the sterilization treatments was evaluated monitoring the reduction in bacterial and fungi populations by standard plate count methods. Sterilization of all carriers was possible by the treatment of 45 minutes the first day and 30 minutes the second day.

Yeast-extract-mannitol (YEM) broth, a widely used laboratory medium for the cultivation of rhizobia, was modified to reduce its cost and made it suitable for medium scale production of rhizobial legume inoculants. Yeast extract and mannitol, the most expensive ingredients, were reduced or substituted with more cheap substrates. With the addition of 1,1 g/L of glutamic acid or food grade sodium glutamate, yeast extract can be reduced to 0,05 g/L without affecting growth. Mannitol can be replaced with 12,5 g/L of pharmaceutical grade glycerin for Bradyrhizobium strains or with 10 g/L of food grade sugar for Rhizobium strains. The symbiotic properties of rhizobia grown on modified media were not affected.

Three soil-compost based carrriers were elaborated and autoclaved by three different treatments of fractionated sterilization in two consecutive days. The efficiency of the sterilization treatments was evaluated monitoring the reduction in bacterial and fungi populations by standard plate count methods. Sterilization of all carriers was possible by the treatment of 45 minutes the first day and 30 minutes the second day.

Yeast-extract-mannitol (YEM) broth, a widely used laboratory medium for the cultivation of rhizobia, was modified to reduce its cost and made it suitable for medium scale production of rhizobial legume inoculants. Yeast extract and mannitol, the most expensive ingredients, were reduced or substituted with more cheap substrates. With the addition of 1,1 g/L of glutamic acid or food grade sodium glutamate, yeast extract can be reduced to 0,05 g/L without affecting growth. Mannitol can be replaced with 12,5 g/L of pharmaceutical grade glycerin for Bradyrhizobium strains or with 10 g/L of food grade sugar for Rhizobium strains. The symbiotic properties of rhizobia grown on modified media were not affected.

El objetivo del presente estudio fue aislar y seleccionar bacterias endofíticas de arroz capaces de inhibir al fitopatógeno Burkholderia glumae THT, así como caracterizarlas por su genética y bioquímica. También se buscó caracterizar la diversidad genética y los factores de virulencia presentes en cepas de B. glumae y de Burkholderia gladioli, otro patógeno de arroz, aisladas de campo. Se colectaron plantas de arroz en 4 departamentos del norte de Perú, y tras la desinfección de tejidos se aislaron bacterias endofíticas por cultivo en agar soya tripticasa (30 °C; 48 h) y en medio selectivo (pH 4,5; 41 °C; 72 h). Se evaluó la actividad antimicrobiana frente a B. glumae THT, la producción de sideróforos y la resistencia a la toxoflavina, toxina producida por este agente. La identificación molecular se realizó mediante BOX-PCR y secuenciación del gen 16S ARNr. Además, s...