Optimization of thermostable á- amylase production by Streptomyces erumpens MTCC 7317 in solid-state fermentation using cassava fibrous residue

Production of á- amylase under solid state fermentation by Streptomyces erumpens MTCC 7317 was investigated using cassava fibrous residue, one of the major solid waste released during extraction of starch from cassava (Manihot esculenta Crantz). Response surface methodology (RSM) was used to evaluate the effect of the main variables, i.e., incubation period (60 h), moisture holding capacity (60 percent) and temperature (50(0)C) on enzyme production by applying a full factorial Central Composite Design. Varying the inoculum concentration (5-25 percent) of S. erumpens showed that 15 percent inoculum (v/w, 2.5 x 10(6) CFU/ml) was the optimum for á- amylase production. Among the different nitrogen sources supplemented, beef extract was most suitable for enzyme production. The application of S. erumpens enzyme in liquefaction of soluble starch and cassava starch was studied. The maximum hydrolysis of soluble starch (85 percent) and cassava starch (70 percent) was obtained with the application of 5 ml crude enzyme (17185 units) after 5 h of incubation.

Lactic acid production from cassava fibrous residue using Lactobacillus plantarum MTCC 1407.

During extraction of starch from cassava, fibrous residue is a major waste released into the environment. Owing to the high starch content (60- 65% on dry weight basis) and organic matter of cassava fibrous residue (CFR), an attempt has been made to utilize it for the production of lactic acid (LA) in semi- solid state fermentation using Mann Rogassa Sharpe medium containing [5 % (wv-1)] CFR in lieu of glucose [2 % (wv-1)] as the carbon source. Response Surface Methodology (RSM) was used to evaluate the effect of main variables, i.e. incubation period, temperature and pH on LA production. The experimental results showed that the optimum incubation period, temperature and pH were 120 hr, 350C and 6.5, respectively. Maximum starch conversion by Lactobacillus plantarum MTCC 1407 to LA was 63.3%. The organism produced 29.86 g of (L+) LA from 60 g of starch present in 100 g of CFR. The LA production yield (i.e. mass LA produced mass starch present in CFR-1 x 100) was 49.76 %.