A Statistical Approach to Optimize Xylitol Production by <i>Debaryomyces nepalensis</i>NCYC 3413 <i>in Vitro</i>

Debaryomyces nepalensis NCYC 3413, halotolerant yeast isolated from rotten apple, was capable of utilizing components of hemicellulose hydrolysate such as glucose, galactose, mannose, xylose and arabinose. The organism utilizes xylose as a sole carbon source and produces xylitol. The Plackett-Burman design was applied to determine the specific medium components affecting xylitol production and found that xylose, K2HPO4, and ZnSO4 were critical in augmenting xylitol production. These significant parameters were further optimized using response surface methodology. The optimum concentrations of xylose, K2HPO4, and ZnSO4 were found to be 100 g/l, 10.6 g/l and 8.9 mg/l respectively. Under these optimal conditions the xylitol production increased from 27 g/l to 36 g/l with a yield of 0.44 g/g (57% increase in total yield). In addition, formation of the by product (glycerol) was decreased under optimal conditions.

Identification of Aflatoxigenic Fungi and Detection of Their Aflatoxin in Red Chilli (<i>Capsicum annuum</i>) Samples Using Direct Cultural Method and HPLC

Aflatoxins are the potential lethal toxin produced by Aspergillus sp. important health hazard throughout the world. In this study, 26 Aspergillus sp. have been isolated from 50 samples of red chilli collected throughout the country. These 26 isolates were grown primarily on agar media to identify the aflatoxin producing species. It is possible to distinguish A. flavus strains from other Aspergillus sp. developing orange colour on the reverse of the plates. The Coconut Cream Agar (CCA) is used to detect aflatoxin producer strains having blue fluorescence when exposed to a UV-light. Several other media were used for morphological characteristics of Aspergillus sp. Out of 26 isolates, four isolates were confirmed as Aspergillus sp. These isolates were subjected to cross contamination with freshly ground, sterile maize and after 15 days of incubation the contaminated maize were analyzed by HPLC and found aflatoxin in each of the sample containing 186 ppb (max.). This study was conducted to assay the ability to produce aflatoxins by the Aspergillus spp. isolated from red chilli (Capsicum annuum L. Solanaceae) available throughout the country. The results found in the experiment are much more behind the acceptable limit according to some international standard. As red chilli is a widely used spice in Bangladesh, the proper controlling measures may be taken for controlling the surveillance of aflatoxinic fungi like as use of bio-pesticides, proper drying method and storage conditions.

Effects of Biochar on the Abundance of Three Agriculturally Important Soil Bacteria

An in vitro study was conducted to make a comparative study of biochar and biomass on soil bacteria. The responses of three agriculturally important bacteria viz., Bradyrhizobium, Sulphate reducing and Iron oxidizing bacteria, were studied. Total viable counts were also made. Three different types of biomasses viz., rice husk, rice straw and saw dust, and biochars produced thereof were used for the study. The biomasses or biochars were applied to the soil at a rate of 5 t/ha. The study included seven different treatments of biomasses and corresponding biochars including a control. Total counts were made on the original materials as well as on the treated soils at 30, 60 and 90 days of incubation. Bacterial count was higher in all the biomass treated soils than the corresponding biochar treated ones including control. Although the presence of Bradyrhizobium, sulphate reducing and iron oxidizing bacteria were not noted in the fresh soils, their presence, however, was noted after incubation periods. The counts of all three bacteria are however lower in the biochar treated soils than the corresponding biomass treated soils. The paper discusses about the microbial soil health vis-à-vis biochar application, indicating that the materials exert negative effect on the soil microbial population and thereby likely to jeopardize soil health and crop production.

Preparation of Water Soluble Yeast Glucan by Four Kinds of Solubilizing Processes

(1→3)-β-D-glucan?from the inner cell wall of Saccharomyces cerevisiae is considered a member of a class of drugs known as biological response modifiers (BRM). However the glucan was an insoluble polysaccharide, which could be the major barrier to the utilization of glucan. In this case, the insoluble glucan was convent into a soluble form by four kind of solubilizing processes. The yield, solubility, chemistry structure and immunoprophylaxis efficacy of the soluble products were compared. Our date suggest that urea has a significant effect on yield, and DMSO has a significant effect on solubility. FT-IR spectra, 13C NMR spectra and helix-coil transition analysis demonstrate that the chemistry structure of native and solubilizing glucans have no significant difference. They still have the triple helical structure. The solubility and immunoprophylaxis efficacy assay indicate that the introduction of phosphate group not only enhanced the solubility of glucan, but also improved the survival rate of mice challenged with E. coli.

3D magnetic field guided sunflower-like nanocatalytic active swarm targeting patients-derived organoids

Nanocatalytic medicine triggering in situ catalytic reactions has been considered as a promising strategy for tumor-selective therapeutics.However,the targeted distribution of nanocatalysts was still low,considering the absence of targeting propulsion capability.Here,encouraged by the fast-developing controllable microrobotics for targeting delivery,a sunflower-like nanocatalytic active swarm(SNCAS)controlled by a three-dimensional(3D)magnetic field was proposed for synergistic tumorselective and magnetic-actively tumor-targeting therapeutics.Furthermore,a patient-derived renal cancer cell 3D organoid was utilized for the verification of the effective tumor therapeutic outcomes.Under the targeted control of 3D magnetic field,the multiple cascade catalytic efficiency of SNCAS based on Fenton reaction was evaluated,resulting in efficient tumor cell apoptosis and death.For the patient-derived organoid treatment,the SNCAS presented significant lethality toward 3D organoid structure to induce cell apoptosis with the collapse of organoid morphology.The targeting efficiency was further enhanced under the magnetic-controllable of SNCAS.Overall,empowered by the magnetic control technology,the synergistic therapeutic strategy based on controllable swarm combined active targeting and tumor-specific catalytic nanomedicine has provided a novel way for advanced cancer therapy.Meanwhile,3D patient-derived organoids were proved as a powerful tool for the effectiveness verification of nanocatalytic medicine.