Cultivation of Bradyrhizobium CB756 on sucrose prefermented by yeast

Abstract

LIE, T. A., MUILENBURG, M., HIEP, N. H., and AYHAN, K. 1992. Cultivation of Bradyrhizobiurn CB756 on sucrose prefermented by yeast. Can. J. Microbiol. 38: 569-572. Saccharornyces cerevisiae, grown with sucrose as a substrate, converts the sucrose to glycerol and produces yeast cells. The yield of glycerol was doubled by adding CaCO,. The fermented medium, containing glycerol and yeast cells, was an excellent medium for the cultivation of Bradyrhizobiurn CB756. Best results were obtained after dilution of the fermented ,medium to 10% (v/v) with a basal salts solution, but even with dilutions of 5 and 2.5%, high numbers of Bradyrhizobiurn CB756 cells were obtained.

Cassava as a Cheap Source of Carbon for Rhizobial Inoculant Production using an Amylase-producing Fungus and a Glycerol-producing Yeast

“…A concentration of 10% (w/ v) glucose in the medium, which produced a glycerol yield of 2.58 g/l, was selected for development of glycerol production in further studies, because such a concentration of glucose could be easily achieved through steamed cassava fermentation. We also determined the effect of CaCO 3 on the yield of glycerol from glucose fermentation, since it was known from the literature that addition of CaCO 3 to the medium enhanced glycerol production (Lie et al 1992). The results showed that the addition of 3 g CaCO 3 /l to the medium during yeast fermentation resulted in 67% increase in glycerol production, compared to yeast fermentation without CaCO 3 (Figure 3b).…”

“…The yeast culture was maintained as an agar slant in a medium modified from Lie et al (1992). This medium contained 1.0 g urea, 1.0 g KH 2 PO 4 , 0.5 g MgSO 4 AE 7H 2 O, 2.5 g yeast extract and 100 g glucose/l, and its pH was adjusted to 5.0 before autoclaving.…”

“…The medium for bradyrhizobial cultivation composed of (in 1 l) 0.5 g NH 4 Cl, 1.0 g KH 2 PO 4 , 0.2 g NaCl, 0.2 g MgSO 4 AE 7H 2 O, 0.04 g CaCl 2 and 0.04 g FeCl 3 , supplemented with 5 g glycerol and 1 g yeast extract (Lie et al 1992). In formulation experiments, sugar prepared from saccharified raw starch material was used for yeast fermentation, which fermented until a high concentration of glycerol was produced.…”

“…However, increasing the CaCO 3 concentration to 10 g/l or higher did not enhance glycerol production further. It is known from the literature that alkaline conditions can also enhance glycerol production from glucose fermentation (James 1928;Vijaikishore & Karanth 1987;Lie et al 1992). Therefore, we conducted an experiment to determine the optimum pH condition for production of glycerol from glucose fermentation using yeast.…”

“…Generally, fastgrowing rhizobia can utilize a variety of sugars such as glucose, sucrose, maltose, whereas bradyrhizobia appear to be nutritionally fastidious (Stowers 1985). Bradyrhizobia can use arabinose, gluconate and some sugar alcohol, such as mannitol and glycerol as a preferred carbon source (Stowers 1985;Lie et al 1992). Generally, mannitol is universally used for cultivation both fastand slow-growing rhizobia (Stowers 1985).…”