Enhanced biobutanol production by optimization of the medium from Clostridium acetobutylicum MTCC 11274 using macroalgae Gracilaria edulis

Clostridial strain Clostridium acetobutylicum MTCC 11274 was employed for producing biobutanol inbatch culture fermentation. The effects of various carbon sources, i.e., xylose, starch, dextrin, glucose, andmannose as well as nitrogen sources, i.e., yeast extract, peptone, beef extract, and soya protein were studiedconventionally (one-factor-at-a-time). It was found that the maximum amount of biobutanol, i.e., 6.27 and 7.40g/l was obtained from 60 g/l glucose and 5 g/l yeast extract, respectively. In addition to this, the interactionsbetween pH, temperature, and glucose concentration were also taken into consideration for the optimization ofbiobutanol production with the help of Central Composite Design (CCD) of Response Surface Methodology.CCD design was used for the optimization of the above-mentioned parameters and low and high values ofvariables were chosen by performing the steepest ascent experiment. The analysis of variance (ANOVA)model was used for estimating the significance of the model coefficients. ANOVA revealed that the modelwas significant (p < 0.05) and the effects of the glucose concentration, pH, and temperature on biobutanolproduction were significant. It was found that 8.56 g/l biobutanol was produced under optimum fermentationconditions with 40 g/l Gracilaria edulis supplemented with 20 g/l glucose as a carbon source

Improving Production of Tacrolimus In Streptomyces Tacrolimicus (ATCC 55098) Through Development of Novel Mutant by Dual Mutagenesis

ABSTRACT Tacrolimus is a polyketide macrolide produced by Streptomyces species which is widely used as anti-fibrotic agent and potent immunosuppressant. In this article dual mutagenesis approach using mutagens (NTG+EMS+UV) was used to develop a mutant strain of Streptomyces tacrolimicus (ATCC 55098) for higher tacrolimus production and this strain showed higher tacrolimus production at 82.5 mg/l. Interestingly; addition of L-Lysine (0.2 g/l) into the production medium further enhanced the tacrolimus production to ~102 mg/l at 7-L fed-batch bioreactor. To the best of our knowledge this is the first report mentioning efficient strain development for higher production of tacrolimus using dual mutagenesis. The obtained data presents an impressive model for higher production of tacrolimus and enhanced our understanding regarding improvement in production capacity of tacrolimus in Streptomyces tacrolimicus.