Biocontrol of Rhizoctonia solani K1 by Iturin A Producer Bacillus subtilis RB14 Seed Treatment in Tomato Plants

Bacillus subtilis RB14 was used as an antagonist against fungal pathogen Rhizoctonia solani K1 to control damping-off diseases in tomato plants. Tomato seeds were treated with B. subtilis RB14 culture. The concentration of bacterial cells for the treatment was about 108 cfu/ml. Treated tomato seeds showed 99% germination index similar to the untreated seeds. Scanning Electron Microscopic observations showed a clear evidence of the presence of B. subtilis RB14 on tomato seed surface. Clear inhibition zone was observed using treated seed in dual plate assay against R. solani K1. B. subtilis RB14 treated seed showed 80% reduction in disease incidence during in vivo plant experiments. B. subtilis RB14 produces lipopeptide antifungal antibiotic iturin A which could suppress R. solani K1. The phenomenon was supported by our observation where we found significant amount of iturin A from the root zone soil of the seed treated plants.

Production of iturin A through glass column reactor (GCR) from soybean curd residue (okara) by <i>Bacillus subtilis</i>RB14-CS under solid state fermentation (SSF)

The present study was conducted with an aim to scale up the production of iturin A using soybean curd residue (okara). Iturin A was produced by indigenous bacterial strain Bacillus subtilis RB14-CS through glass column reactor (GCR) under solid state fermentation (SSF) was characterized. The enhanced iturin A production was observed with respect to enhanced substrate bed height when SSF was conducted in Erlenmeyer flask. To check the effect of substrate bed height on iturin A production under SSF of okara, GCR was introduced. Substrate bed height of 15 cm was suitable for iturin A production which was about 2700 mg/kg wet substrate. The observed iturin A production by the aerobic bacteria Bacillus subtilis in nearly anaerobic condition in such high substrate bed for SSF is a wonderful finding for development of SSF system in future.

Quality of Water Adjusted Sources and Storage in the Households of the Sanitized Villages in Area of National Program of Sanitized Schools and Villages at Tshopo Province in Republic Democratic of Congo

Introduction: The present research paper aims at assessing the bacteriological water quality in households and at provisioning points, and so factors of water deterioration. Method: a transverse study has been conducted during the period starting from 11 up to 28 October 2018 within 6 Health Zones (HZ) in Tshopo Province integrated in National Program of Schools and Sanitized Villages (NPSSV). Water samples have been collected within 300 reserves of households and 30 water provisioning and analysed points in order to find out water contamination factors. The frequencies and raw OR have been estimated at (p < 0.05) valued significative. Results: fecal coliforms (80% CI95: 75% - 85%) and total (97% CI95: 95% - 99%) were significantly present in water reserves and the presence of Escherichia coli were at about 27% (IC95 22% - 32%). These proportions were correspondingly at 63%, 90% and 10% at water provisioning. The fecal coliforms were the highest in water reserves of sanitized villages (p < 0.05) and Escherichia coli were at about three times higher in traditional sources (17% vs 6%). The duration of water conservation was around 48 hours and more (OR = 4.41;IC95: 1.92 - 10.11), water classification of sanitized risk “intermedium” and the recipients of conservation with bottleneck were associated with the presence of E.coli in water (p < 0.05). Conclusion: water from provisioning sources and household reserves are severely polluted and water quality is not good at consumption point and at provisioning point. The reinforcement of safety measures at water points, reduction of conservation length and hygienic water cleaning of storage water recipients are necessary to assure quality of water.