Sequential statistical optimization of lactose-based medium and process variables for inulinase production from Penicillium oxalicum BGPUP-4

Coproduction of inulinase and invertase by Galactomyces geotrichum in whey-based medium and evaluation of additional nutrients

The purpose of this research was to evaluate the suitability of whey as an effective medium for the coproduction of inulinase and invertase by an oleaginous yeast Galactomyces geotrichum and to investigate the effects of some additional carbon and nitrogen sources. The nutritional factors and composition of the medium have a great impact on the production pathways of microbial enzymes. To deepen the research, a Taguchi design was employed to quickly scan the best conditions. First, the cheese whey was partly deproteinized and investigated as the sole medium for the yeast. The next step was performed to study the effects of inulin, sucrose and lactose as carbon sources and ammonium sulfate, yeast extract and casein as nitrogen sources. All analyses (Taguchi and ANOVA) were performed using Minitab software. Whey-based medium without any additional carbon and nitrogen sources gave inulinase and invertase activities as 54.6 U/mL and 47.4 U/mL, respectively. Maximum inulinase activity was obtained as 77.9 U/mL using inulin as the carbon source without any nitrogen source. The highest I/S ratio was found as 2.08. On the other hand, the highest invertase activity was carried out as 50.85 U/mL in whey-based medium using lactose as carbon source without any additional nitrogen source. This is the first report about partly deproteinized whey-based medium utilization for simultaneous inulinase and invertase production by G. geotrichum TS-61. Moreover, the effects of carbon and nitrogen sources were investigated in detail.

Wheat Growth Dependent Succession of Culturable Endophytic Bacteria and Their Plant Growth Promoting Traits

Endophytic bacteria present ubiquitously in all plant parts. Their community structure may vary depending on plant tissue and growth condition. This work mainly focused on exploring the diversity of culturable nitrogen-fixing endophytic bacteria in above-ground plant parts of wheat by harvesting it during various growth points (Seed stage, 1st, 2nd, and 3rd month old plants, respectively). Distinct endophytic bacterial colonies were selected on Jensen's agar plate. Based on the 16S rRNA sequencing, 43 putative nitrogen-fixing endophytic bacteria were identified. Most of the isolates were found unique to the plant growth phase except for Pseudomonas sp., Bacillus sp., Paenibacillus sp., Microbacterium sp., Exiguobacterium sp. Further, endophytic bacteria were scrutinized for their plant growth promoting traits. They were found positive for IAA production (100%), P-solubilization (21%), Zn-solubilization (63%), ammonia production (93%), and nifH gene (33%). Extracellular enzyme production was found positive for cellulase (98%), pectinase (98%), and protease (100%). Their endophytic colonization ability was assessed using reactive oxygen species (ROS) induction assay, upon their entry inside the host plant.

The whole-genome sequence analysis of Enterobacter cloacae strain Ghats1: insights into endophytic lifestyle-associated genomic adaptations

Enterobacter cloacae is normally considered to be an opportunistic human pathogen. Here, we report on the whole-genome sequence of an endophytic E. cloacae, strain "Ghats1", isolated from leaves of the medicinal plant Coscinium fenestratum Gaertn. Functional analysis of the Ghats1 genome revealed an enrichment for genes involved in the uptake and exchange of nutrients, for chemotaxis and for plant colonization. Unexpectedly though, there were no ORFs belonging to the "virulence factors and antibiotic resistance". Moreover, the presence of hydrolytic enzymes and motility functions reveals the characteristics of an endophyte lifestyle of a bacterium that can colonize and adapt to plant environment. These results provide a better understanding of an endophytic lifestyle through plant-microbe interaction, which can be further exploited as a biocontrol agent.

Biocatalytic strategies for the production of high fructose syrup from inulin

The consumption of natural and low calorie sugars has increased enormously from the past few decades. To fulfil the demands, the production of healthy sweeteners as an alternative to sucrose has recently received considerable interest. Fructose is the most health beneficial and safest sugar amongst them. It is generally recognised as safe (GRAS) and has become an important food ingredient due its sweetening and various health promising functional properties. Commercially, high fructose syrup is prepared from starch by multienzymatic process. Single-step enzymatic hydrolysis of inulin using inulinase has emerged as an alternate to the conventional approach to reduce complexity, time and cost. The present review, outlines the enzymatic strategies used for the preparation of high fructose syrup from inulin/inulin-rich plant materials in batch and continuous systems, and its conclusions.