Micropropagation of Solanum lycopersicum L. using chemical free formulated organic plant growth media

Micropropagation is currently the most commercially effective plant biotechnology that helps in the rapid generation of a large number of clonal plants of many plant species in a short period. Effective protocol was developed for in vitro micropropagation of Solanum lycopersicum (tomato) using chemical-free organic vermicompost (VC) extract medium. This experiment aims to expose the advancement in plant tissue culture technique by using synthetic Murashige and Skoog medium (MS) medium and a chemical-free organic VC (30%) extract along with 4% coelomic fluid (obtained from the earthworms Eudrilus eugeniae) as a growth medium for in vitro studies. The response of roots, leaves, shoots, and nodes in both synthetic (MS) medium and chemical-free organic VC extract medium was compared statistically using Student’s t-test. Statistically significant differences for the number of roots (P =0.011), leaves (P=0.012), and nodes (P=0.001) between the two media were reported. Both media showed the same shoot induction where no significant differences were reported with a P value of 1.000 for shoots. The protocol has led to a 100% plant survival rate on chemical-free organic vermicompost extract media. The results have also shown a significant difference in growth rate between two different media. Vermicompost and coelomic fluid used in media have antimicrobial activities which led to minimal contamination level and this consequently minimized timely subculturing. Through our studies, we found that chemical-free organic vermicompost extract media proved to be more economical and a better prospective than MS media for in vitro propagation of tomato.

Evaluation of some biophysical characteristics of five silicate solubilizing bacteria isolated from different ecosystems

Silicate solubilizing bacteria (SSB) are key microorganisms to solubilize silicate minerals in the soil. Silicon helps to increase the growth and yield of plants and to enhance the environmental stress tolerance capability of plants. The aim of this study was to evaluate the effect of several factors like pH, salinity, and temperature on silicate solubilizing capacity of five selected SSB. Moreover, phosphorus solubilizing, nitrogen-fixing and indole-3-acetic acid (IAA) synthesizing capacity of these five bacteria were also tested. Liquid soil extract medium containing 0.25% Mg2O8Si3 was used in this study. Abilities of bacteria in phosphorous solubility, nitrogen fixation, and IAA synthesis were tested in NBRIP, Burk’s and NBRIP containing 100 mg L-1 tryptophan media, respectively. The results of the study indicated that five SSB showed their high capacity in silicate solubilization at pH 7.0, NaCl 0.0% and 35oC. However, at a concentration of NaCl 0.5%, these five SSB still solubilized well silicate mineral. Moreover, they also solubilized effectively three different insoluble phosphate sources of Ca3(PO4)2, AlPO4 and FePO4 with a range varied between 105.8 and 928.7 mg P2O5 L-1, 33.9 and 49.6 mg P2O5 L-1, and 1.94 and 34.1 mg P2O5 L-1, respectively. They also fixed biologically nitrogen with a range from 1.37 to 5.09 mg NH4+ L-1 after 2 incubation days. Finally, they also showed their ability in IAA synthesis with an amount between 4.85 and 51.5 mg IAA L-1. In short, these five SSB in this study not only had the ability in silicate solubilization but also had other functions in plant growth promotion.

Production of Microbial Exopolysaccharide by Cost-effective Medium Opimization Method

Microbial exopolysaccharide (EPS) emerged as a fast and high yielding sustainable polymeric substance which can be used as an alternative to synthetic polymer in industry. In this study, the influence of various nutritional and environmental factors of fermentation medium on bacterial growth and EPS production was evaluated by one factor at a time optimization. Efficient production medium was chosen from four different basal media and its carbon and nitrogen substrates were varied among organic and inorganic sources. Feasibility of bacterial utilization of some agricultural wastes as carbon and nitrogen sources to synthesize exopolysaccharide was compared. Carbon source of the fermentation medium was replaced with hydrolysates of sugarcane baggasse (SCB), sweet potato peels (SPP) or ripe plantain peels (RPP) at various concentrations while the nitrogen substrates was replaced with extracts of poultry droppings (PP), groundnut pod (GP) or beans bran (BB). Response results observed from single factor optimization were explored as center points to design a model for Response Surface Methodology study. Cell growth was determined from the biomass population of the fermentation broth after 5 days of incubation in a rotary shaker at 120 rpm at 30ºC. EPS was precipitated with pre-chilled ethanol (at 4ºC) from cell-free broth and overnight incubation at 4ºC. Total carbohydrate content was estimated by phenol-sulphuric acid method. Result obtained showed that 2% concentration Hydrolysate of SPP containing medium gave maximum yield of 2.26 g EPS/l of the medium as compared to sucrose containing medium with yield of 1.25 g EPS/l of the medium while highest production yield of 9.46 gEPS/l of the medium was obtained from 10 g/l BB extract medium as compared to yeast extract medium (5.41 gEPS/l). Results indicated that agricultural wastes such as sweet potato peel hydrolysate and bean bran extract could be developed as inexpensive alternative route to synthesize EPS from bacteria than inorganic substrates.

Production of Microbial Exopolysaccharide by Cost-effective Medium Optimization Method

Microbial exopolysaccharide (EPS) emerged as a fast and high yielding sustainable polymeric substance which can be used as an alternative to synthetic polymer in industry. In this study, the influence of various nutritional and environmental factors of fermentation medium on bacterial growth and EPS production was evaluated by one factor at a time optimization. Efficient production medium was chosen from four different basal media and its carbon and nitrogen substrates were varied among organic and inorganic sources. Feasibility of bacterial utilization of some agricultural wastes as carbon and nitrogen sources to synthesize exopolysaccharide was compared. Carbon source of the fermentation medium was replaced with hydrolysates of sugarcane baggasse (SCB), sweet potato peels (SPP) or ripe plantain peels (RPP) at various concentrations while the nitrogen substrates was replaced with extracts of poultry droppings (PP), groundnut pod (GP) or beans bran (BB). Response results observed from single factor optimization were explored as center points to design a model for Response Surface Methodology study. Cell growth was determined from the biomass population of the fermentation broth after 5days of incubation in a rotary shaker at 120 rpm at 30oC. EPS was precipitated with pre-chilled ethanol (at 4oC) from cell-free broth and overnight incubation at 4oC. Total carbohydrate content was estimated by phenol-sulphuric acid method. Result obtained showed that 2% concentration Hydrolysate of SPP containing medium gave maximum yield of 2.26g EPS/l of the medium as compared to sucrose containing medium with yield of 1.25 g EPS/l of the medium while highest production yield of 9.46 gEPS/l of the medium was obtained from 10 g/l BB extract medium as compared to yeast extract medium (5.41 gEPS/l). Results indicated that agricultural wastes such as sweet potato peel hydrolysate and bean bran extract could be developed as inexpensive alternative route to synthesize EPS from bacteria than inorganic substrates.

Effect of peptones on the ability of plant pathogenic bacteria to grow on media supplemented with copper sulphate

The extensive use of copper compounds for control of bacterial plant pathogens could lead to selecting strains of the pathogens that are copper-resistant. The ability to grow on a medium supplemented with copper, and therefore the concentration of copper to which bacterial strains are resistant, depends on the composition of the medium used for the test. The effects of different peptones (casitone and proteose peptone No. 3) and different media on the ability of strains of Pseudomonas syringae to grow in presence of copper were determined. Similar results were obtained when casitone was substituted with proteose peptone No. 3 in casitone yeast extract medium, but not when those two peptones were interchanged in King’s B medium. In water, casitone allowed strains of P. syringae pv. actinidiae (Psa) to grow in the presence of higher amounts of copper than proteose peptone No. 3 did. In all cases, resistance to copper was increased with increased peptone concentration.

Biotransformation of major ginsenoside Rb1 to pharmacologically active ginsenoside Rg3 through fermentation by Weissella hellenica DC06 in newly developed medium

The study was conducted to develop an edible and low cost growth medium for cultivation of Weissella hellenica DC06, a lactic acid bacteria (LAB) and to study whether, the medium is suitable for bioconversion of major ginsenoside Rb1 into ginsenoside Rg3 through fermentation by W. hellenica DC06. Fourteen different media compositions were investigated to cultivate W. hellenica DC06. Among these, W. hellenica DC06 exhibited the highest growth in media containing 20 g/l radish, 20 g/l glucose, and 10 g/l yeast extract (Medium 3). The optical density of W. hellenica DC06 cultivated in medium 3 reached 1.8 (1.066 x 1010 CFU/ml) after 24 h of incubation. Importantly, the optimized medium was approximately four times cheaper compared to MRS medium. In addition to being economical, the new medium was also edible. Also W. hellenica DC06 showed strong fermentation ability in newly developed medium regarding on major ginsenoside Rb1 biotransformation. Ginsenoside Rb1 was converted into pharmacologically active ginsenoside Rg3 in new medium. In contrast,W. hellenica DC06 showed weak fermentation ability in MRS medium where ginsenoside Rb1 was converted intoginsenoside Rd. The transformation products were analyzed by TLC, and HPLC. Within seven days of fermentation, almost all ginsenoside Rb1 was decomposed and converted into Rg3 in optimized medium. W. hellenica DC06 hydrolyzed two glucose moieties attached to the C-20 position of the ginsenoside Rb1aglyconeand synthesized Rg3 in newly developed medium.Bangladesh J. Sci. Ind. Res. 51(4), 271-278, 2016