Poor competitiveness of Bradyrhizobium in pigeon pea root colonisation in Indian soils

Background Pigeon pea, a legume crop native to India, is the primary source of protein for more than a billion people in developing countries. The plant can form symbioses with N2-fixing bacteria, however reports of poor crop nodulation in agricultural soils abound. We report here study of the microbiota associated with pigeon pea, with a special focus on the symbiont population in different soils and vegetative and non-vegetative plant growth. Results Location with respect to the plant roots was determined to be the main factor controlling the microbiota followed by developmental stage and soil type. Plant genotype plays only a minor role. Pigeon pea roots have a reduced microbial diversity compared to the surrounding soil and select for Proteobacteria and especially for Rhizobium spp. during vegetative growth. While Bradyrhizobium, a native symbiont of pigeon pea, can be found associating with roots, its presence is dependent on plant variety and soil conditions. A combination of metagenomic survey, strain isolation and co-inoculation with nodule forming Bradyrhizobium spp. and non-N2 fixing Rhizobium spp. demonstrated that the latter is a much more successful coloniser of pigeon pea roots. Conclusions Poor nodulation of pigeon pea in Indian soils may be caused by a poor Bradyrhizobium competitiveness against non-nodulating root colonisers such as Rhizobium. Hence, inoculant strain selection of symbionts for pigeon pea should not only be based on their nitrogen fixation potential but more importantly on their competitiveness in agricultural soils

Food for the Stomach or Fuel for the Tank: What do Prices Tell Us?

The “food vs. fuel” debate has been difficult to resolve without letting the data speak. In this paper we investigate the short run interactions and the long-run equilibrium relationship between food and fuel prices. Results from cointegration analysis indicate a long-run equilibrium relationships between these prices. A closer examination of the price dynamics between ethanol and three food prices revealed that the corn-soybean linkage plays a key role in the fuel-food long-run relationship. Our results indicate that ethanol prices Granger cause corn prices, while no individual agricultural commodity appears to Granger cause ethanol prices. However, corn and soybean as a single group had a significant impact on the ethanol market

Isolation and Optimization of Culture Conditions of a Bioflocculant-Producing Fungi from Kombucha Tea SCOBY

Biolocculants are gaining attention in research due to their environmental friendliness and innocuousness to human in comparison to the conventional flocculants. The present study aimed to investigate the ability of fungi from Kombucha tea SCOBY to produce effective bioflocculant in bulk. A 16S rRNA gene sequence analysis was utilized to identify the isolate. The medium composition (carbon and nitrogen sources) and culture conditions (inoculum size, temperature, shaking speed, pH, and time) were optimized using one-factor-at-a-time method. The functional groups, morphology, and crystallinity of the bioflocculant were evaluated using Fourier transform infrared (FT-IR), scan electron microscope (SEM) and X-ray diffractometry (XRD). The fungus was found to be Pichia kudriavzevii MH545928.1. It produced a bioflocculant with flocculating activity of 99.1% under optimum conditions; 1% (v/v) inoculum size, glucose and peptone as nutrient sources, 35 °C, pH 7 and the shaking speed of 140 rpm for 60 h. A cumulus-like structure was revealed by SEM; FT-IR displayed the presence of hydroxyl, carboxyl, amine, and thiocynates. The XRD analysis demonstrated the bioflocculant to have big particles with diffraction peaks at 10° and 40° indicating its crystallinity. Based on the obtained results, P. kudriavzevii MH545928.1 has potential industrial applicability as a bioflocculant producer

Isolation and Optimization of Culture Conditions of a Bioflocculant-Producing Fungi from Kombucha Tea SCOBY

Biolocculants are gaining attention in research due to their environmental friendliness and innocuousness to human in comparison to the conventional flocculants. The present study aimed to investigate the ability of fungi from Kombucha tea SCOBY to produce effective bioflocculant in bulk. A 16S rRNA gene sequence analysis was utilized to identify the isolate. The medium composition (carbon and nitrogen sources) and culture conditions (inoculum size, temperature, shaking speed, pH, and time) were optimized using one-factor-at-a-time method. The functional groups, morphology, and crystallinity of the bioflocculant were evaluated using Fourier transform infrared (FT-IR), scan electron microscope (SEM) and X-ray diffractometry (XRD). The fungus was found to be Pichia kudriavzevii MH545928.1. It produced a bioflocculant with flocculating activity of 99.1% under optimum conditions; 1% (v/v) inoculum size, glucose and peptone as nutrient sources, 35 °C, pH 7 and the shaking speed of 140 rpm for 60 h. A cumulus-like structure was revealed by SEM; FT-IR displayed the presence of hydroxyl, carboxyl, amine, and thiocynates. The XRD analysis demonstrated the bioflocculant to have big particles with diffraction peaks at 10° and 40° indicating its crystallinity. Based on the obtained results, P. kudriavzevii MH545928.1 has potential industrial applicability as a bioflocculant producer