Physiological and Chemical Studies on the Bioconversion of Glycyrrhizin by Aspergillus niger NRRL595

Glycyrrhizin (GL), the well-known sweet saponin of licorice, has been used as a food-additive and as a medicine. Its aglycone, glycyrrhetic acid (GA) showed antiinflamatory, antiulcer and antiviral properties. GA is now produced form GL by acid hydrolysis. However, it is difficult to obtain GA in a good yield by using this method, because many by-products are also produced. Screening of different microorganisms (13 bacteria, 2 yeasts and 23 fungi) for production of GA from GL revealed that Aspergillus niger NRRL 595 produced the highest yield of GA. The bioconversion of GL by A. niger NRRL 595 for 96 h, followed by isolation and purification of the transformation products led to the separation of two conversion products, namely: GA and 3-oxo-GA. Confirmation of the identity of these products was established by determination of their Rf values, m.p., and IR, UV, MS and NMR spectra. The conditions for cultivation of this fungus with the maximum hydrolytic activity for the maximum yield of GA were investigated. Based on the results, A. niger NRRL 595 was cultivated with a medium composed of 1.75 % GL, 0.5 % glucose, 0.8 % corn steep liquor at pH 6.5 at 32 °C for 96 h. The cultivation of fungal cells under the latter conditions afforded GA and 3-oxo-GA in a yield of 65 % and 22 %, respectively.

Some physiological aspects affecting lipid and protein production by candida parapsilosis growing on solar

Variations in the mineral composition of the medium, its hydrocarbon and nitrogen sources, played a significant role in the productivity of lipids and protein by Candida parapsilosis wild type, KSh 21. Among the petroleum fraction tested were gasolene, kerosene and solar as well as El-Alameen crude oil. Solar at a concentration of 3% v/v proved to be the best carbon source utilized by the organism giving the highest frementation yields. Factors such as fermenation time course, solar level, pH relations [initial and biffered], nature and concentration of nitrogen source, phosphate level and addition of magnesium sulphate and soduim chloride were also tested

Physiological profile of nitrogen-fixation by Azomones macrocytogenes

The N[2]fixing efficiency of Azomonas macrocytogenes is markedly affected by the volume of the culture medium as well as by the rate of shaking. The organism exhibits its highest N[2]fixing potentiality when grown in 250 ml Erlenmeyer flask containing 150 ml medium and shaked at 100 rpm. The optimal pH value for N[2]fixation is achieved with the medium adjusted to pH 5.8 using phosphate buffer. Maximal total N[2]fixed as well as the efficiency of N[2]fixation are achieved after 8 days of incubation. A low glucose level [5g/1] permits high values of total N[2]fixed and efficiency of N[2]fixation. The addition of sodium succinate [2g/1] supports better total N[2]fixed as well as higher N[2]fixing efficiency

Single cell protein production from orange waste

Sporotrichum thermophile was successfully used for single cell protein [SCP] production using crude orange waste [OW] as the sole carbon source. Lower fermentation yields were achieved with delignified or depectinized OW containing media. However, the oil-free OW supported the maximum growth yields, holocellulose assimilation as well as SCF outputs [49%] after 20 days of incubation. The analyses of fermentation residue [fungal biomass unfermented OW], revealed that about 2/3 of the crude OW, s holocellulase was consumed by the fungus. Similarly, the amounts of lignin and pectin constituents were reduced nearly to half the original contents. On the contrary, highest percentage of crude protein [41%] was recorded. The obtained protein proved to contain all essential amino acids. Which were mostly compared favourably with those of the FAD guidline and of soy bean oil meal

Some nutritional requirements influencing the utilization of orange waste by Sthermophile for protein production

Snorutrichum thermophile was used for single cell protein [SCP] production in a medium containing orange waste as the sole carbon source. The growth and SCP production of the Fungus were markedly affected by the orange waste [OW] level. Optimal OW concentration for biomass and SCP yields was found to be 40 g/1. Ammonium nitrate as a nitrogen source at 3.5 g/l level supported high growth and maximal protein production [42.4%]. The addition of K[2] HP0[4], MgSO [4]. 7H[2]O, KCl and FeSO [4]. 7H[2]O at concentrations of 15 mg/1 for the latter salt and 0.5 g/1 for each of the other salts allowed better fermentation yields