Recently, xylanase has become an essential option for environmental friendly industrial biotechnological applications and the rising demand for its large scale production urge to take the advantage of statistical approach of optimization to investigate the interactive effects of prominent process factors involved to enhance xylanase production. In the present study, xylanase production from Streptomyces sp. strain ER1 isolated from Cochin estuarine soil; was optimised using statistical designs- Plackett-Burman and Central composite design. Plackett-Burman design was used to identify important fermentation condition factors affecting the xylanase production using beechwood xylan as the substrate. The optimum levels of these significant factors were determined employing the Central Composite Design. Out of the thirteen factors screened, concentration of beechwood xylan and olive oil, agitation speed, and inoculum age were recognized as the most significant factors. By analyzing the response surface plots and using numerical optimization method, the optimal levels for concentration of xylan and olive oil, agitation speed and inoculum age were determined as 0.37%, 33.10 mg/L, 42.87 RPM and 21.05 h, respectively. The optimised medium resulted in a 1.56-fold increased level of the xylanase (10,220 U/mL) production compared to the initial level (3986.444 U/mL) after 120 h of fermentation. The purified enzyme could successfully clarify orange, mousambi and pineapple juice to 20.87%, 23.64% and 27.89% respectively. Thus the present study has proved that Streptomyces sp. strain ER1 (KY449279) is a potential and useful organism for xylanase production and its purified enzyme could clarify the selected fruit juices.

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Microalgal biomass has emerged as a promising alternative to replace plant-based biofuel feedstock due to its higher lipid productivity. But cultivation of microalgae in expensive analytical grade culture media is a major obstacle in feasible algal biofuel production. Hence the present investigation was carried out to find an alternative, low-cost culture medium for the increased biomass yield and biochemical production of microalga, Desmodesmus subspicatus MB. 23. The strain was cultivated in different concentrations of 19: 19: 19 NPK media and checked for the algal biomass production and biochemical accumulation. Maximum algal cell density (5290 ×104 cells/ ml), biomass yield and productivity (2.72 g/L, 60.87 mg/L/d) was attained in 2 g/ L NPK fertilizer medium, whereas 1g/L medium exhibited increased chlorophyll production (chl-a, 4.7 mg/g d wt, chl-b 1.7 mg/g d wt). High level of carotenoid accumulation (4.6 mg/g d wt) as well as lipid accumulation (29.5%) was found in 0.5g/L fertilizer media and Fatty acid methyl ester analysis of the strain showed abundant production of C16 and C18 fatty acids. Findings of the current study proved that, lower concentration of 19:19:19 NPK fertilizer can be used for the enhanced production of green microalgae. Other than cost effective biofuel production, NPK fertilizer grown D. subspicatus can also be used for the production of a wide range of metabolites such as food and feed additives, pharmaceuticals and cosmetics.