Valorization of potato peel for production of alginate and optimization of the process through response surface methodology (RSM) by using Azotobacter nigricans

Alginic acid, the heteropolysaccharide, obtained from farmed brown seaweeds is an industrially important biopolymer. As Pakistan lacks the required sea weeds, so meets the demand by importing it from technically advanced countries. The recent study was intended to evaluate the capacity of potato peels (Solanum tuberosum) for alginate biosynthesis by Azotobacter nigricans using solid-state fermentation. Different fermentation parameters were optimized and their interaction studied using central composite design of response surface methodology (RSM). After optimization, the highest amount of alginate (205 mg/gds) was attained after 4 days of incubation at pH 7.5, temperature 30 °C, 1 mL of inoculum, and 0.1% corn steep liquor (CSL). The F-value was estimated as 38.75 and p value, 0.00, using a statistical tool that specifies the planned model was highly significant. Coefficient of determination (R2) was used to calculate the goodness of fit of the model and value of 98.6 % indicated the precision of the model with all the factors having significant effect on production process. Identification of alginate produced was done by FTIR and quantification by HPLC method. It was calculated as 96.4 % pure in comparison to standard. The outcomes specified that alginate can be proficiently manufactured by solid-state fermentation by consuming cheap food waste as the substrate.