Parag S. Saudagar

Clavulanic acid: A review

Natural antibiotics are almost universal secondary metabolites, not essential for the growth of the producing organisms generally produced at low growth rates or after growth has ceased. Clavulanic acid (CA), a naturally occurring powerful inhibitor of bacterial beta-lactamases is a major beta-lactam antibiotic produced by organism Streptomyces clavuligerus and is active against a wide spectrum of Gram-positive and Gram-negative bacteria. The review discusses the biosynthetic pathway, fermentative production, downstream processing and applications of CA.

Fermentative production of curdlan.

Curdlan was produced by pure culture fermentation using Agrobacterium radiobacter NCIM 2443. Three different carbon sources (glucose, sucrose, maltose) were selected for study. Sucrose was found to be the most efficient. Utilization of sugar during the course of fermentation was studied, and the data were correlated to the production of curdlan. Curdlan mimics a secondary metabolite, in that its synthesis is associated with the poststationary growth phase of nitrogen-depleted batch culture. This was inferred from the results obtained from utilization of nitrogen. Regulation of pH at 6.1±0.3 resulted in an increased yield of curdlan from 2.48 to 4.8 g/L, and the corresponding increase in succinoglucan production was from 1.78 to 2.8 g/L. An attempt was made to increase curdlan production by the addition of the uridine nucleotides UMP and UDP-glucose to the fermentation broth. It was found that UDP-glucose at 0.8 µg/mL and UMP at 0.6 µg/mL served as precursors for curdlan and succinoglucan production when added after 18 h of nitrogen depletion in the fermentation broth.

Media Optimization for the Production of ?- Linolenic Acid by Cunninghamella echinulata var.elegans MTCC 552 Using Response Surface Methodology

?- Linolenic acid (GLA) is an intracellular primary metabolite produced by some plants and fungal species via several distinct biosynthetic pathways. It is an essential fatty acid, and is mainly used in treatment of various diseases such as rheumatoid arthritis, multiple sclerosis, schizophrenia, atopic eczema and premenstrual syndrome. It is also a precursor of a number of biologically active compounds. In present work, strains of Cunninghamella echinulata var.elegans MTCC 552, Mucor rouxii MTCC 386, Mucor hiemallis MTCC 1278 and Rhizopus stolnifer MTCC 2591 were screened for maximum production of GLA. Cunninghamella echinulata var. elegans MTCC 552 produced maximum GLA (13.7 ± 0.31 mg/g of DCW), and hence selected for further work. Many crucial factors that affect GLA production were optimized in two steps. In the first step, one factor at a time method was used to investigate the effects of media constituents. Subsequently, in the second step, concentration of media components was optimized using Response Surface Methodology (RSM). These optimizations increased the GLA production to 19.8 ± 0.35 mg/g of DCW.