Production of biotechnological useful metabolites by Mucor racemosus in Czapek-Dox liquid media supplemented with synthetic detergent

The capacity of native isolate Mucor racemosus to produce several potentially useful metabolites in a liquid Czapek-Dox medium supplemented with powder anionic-type detergent MERIX (Henkel, Serbia) at concentrations of 0.3% (D3) and 0.5% (D5) was examined in this study. The changes of pH values, the total protein content, activities of acid and alkaline invertase, ?-amylase, as well as biomass dry weight were evaluated during fungal growth from inoculation until the 16th day. In addition, the qualitative and quantitative amino acids content of 16 days old fermentation broth was determined by HPLC. D3 considerably enhanced the biomass dry weight (43%), ?-amylase activity (49.59%) and the quantity of arginine (40.38%), and also influenced the production of a high amount of proteins (5.32 g/L). D5 significantly enhanced the biomass dry weight (53%), the quantity of arginine (119.09%) and alanine (192.79%) and induced the production of valine, serine and glutamate. In the D5 medium, ?-amylase retained 100% of its activity. The acid and alkaline invertase activity was moderately inhibited by D3 and D5. The obtained results may have considerable biotechnological, industrial and environmental potential.

Effects of sodium nitroprusside activity of acid and alkaline invertases and alkaline phosphatase in lemongrass (Cymbopogon flexuosus Steud) Wats

Here we report the effects of SNP, a nitric oxide donor on sucrose metabolizing enzymes, acid and alkaline invertase (EC 3.2.1.26 and 3.2.1.153) and ubiquitous alkaline phosphatase (EC 3.1.3.1) in four lemongrass varieties viz., Krishna, Cauveri, Nima and Cheerharit. For the study, two 15 d lemongrass tillers were cut and immediately dipped into the test tubes containing SNP solution (5 mL) of variable strength (1 to 5 mM) and one without SNP (as control); kept for 4 h under mild sunlight. The results revealed that moderate SNP concentration (2 mM) was most effective, caused drastic reduction (40%) in protein content in var. Nima followed by Krishna (33%), Cauveri (17%) and Cheerharit (12%). In contrast, SNP (1 mM) has impressively enhanced protein content in all the lemongrass varieties. The SNP (2 mM) markedly inhibited the activity of acid invertase by 38% in Cheerharit, 35% Nima and 28% Cauveri whereas and alkaline invertase by 21, 28 and 24% respectively in var. Cheerharit, Nima and Krishna. Similarly, SNP (5 mM) severely inhibited (~ 63%) the activity of the ALP in lemongrass var. Cauveri and Nima, 50% in Krishna and relatively less 23% in Cheerharit as compared to the control. However, in var. Nima, 50% loss in ALP activity had already been occurred after 2 mM SNP treatment. These results primarily suggests that NO interferes sucrose metabolism by anonymously hindering the activity of acid and alkaline invertase and ubiquitous alkaline phosphatase in lemongrasses.

NITROGEN FIXATION AND CARBON METABOLISM IN VICIA FABA ROOT NODULES OVER ONTOGENY

The evolution of growth, nodulation, nitrogen fixation, and activities of root-nodule enzymes related to sucrose breakdown (sucrose synthase, alkaline invertase), pentose phosphate pathway (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase), malate dehydrogenase, phosphoenolpyruvate carboxylase, and NADP-dependent isocitrate dehydrogenase, were followed over the complete life-cycle of faba bean in a growth chamber. The aim was to study the ontogenic changes of these parameters to obtain information on the carbon metabolism in nodules ofVicia faba, an amide-exporting legume. The maximum values of the relative growth rate and the specific acetylene-reducing activity were registered during the vegetative period. At pod-filling, the specific and total acetylene-reducing activity per plant declined in parallel with the enzyme activities of carbon metabolism. Contrary to reports for other legume species, inV. fabaroot nodule activity of sucrose synthase exceeded alkaline invertase values by 2-fold or more during the vegetative period. The activity of the two enzymes was similar at flowering and pod formation. The enzymes of carbon metabolism registered two maxima, one before and one after a trough (day 32), which marked the change from the vegetative to the reproductive period.

An Alternative and Inexpensive Assay for Plant Invertases

The glucose-6-phosphate dehydrogenase (G-6-PDH) and glucose oxidase methods are commonly adapted for plant invertase assay. A disadvantage of the G-6-PDH assay is the relatively high cost of the coupling enzymes and cofactors. A disadvantage of the glucose oxidase method, which uses a glucose kit (Sigma, 510-A), is the presence of high activities of acid invertase and alkaline invertase in the PGO enzyme formula (peroxidase and glucose oxidase), which gives a falsely high invertase activity value. An alternative and inexpensive coupled assay was developed for enzymatic assay of plant invertases. In this assay, ADP produced from phosphorylation of glucose and fructose (hydrolysis products of invertases) is coupled to oxidation of NADH by the enzymes pyruvate kinase and lactate dehydrogenase in presence of phosphoenolpyruvate and NADH. This method was compared with the glucose-6-phosphate dehydrogenase method by using protein preparations derived from plant materials of three different species. Statistical analysis indicated that the alternative assay was similar in accuracy to the glucose-6-phosphate dehydrogenase method, with an advantage of reducing the cost from $0.85 to $0.35 per assay.