PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
SCLEROGLUCAN PRODUCTION WITH ENVIRONMENTAL ISOLATES OF Sclerotium rolfsii BY USING POTATO- AND CORN-DERIVED ALTERNATIVE SUBSTRATES
Autor/es:
ALEJANDRA L. VALDEZ; MARIANA E. DANILOVICH; CECILIA SALES-CAMPOS; JULIA I. FARIÑA; OSVALDO D. DELGADO
Reunión:
Workshop; II Workshop Polímeros Biodegradables y Biocompuestos III Workshop of the project BIOPURFIL, Bio-based Polyurethane Composites with Natural Fillers; 2015
Resumen:
Scleroglucan is a neutral, hydrosoluble exopolysaccharide (EPS) with a b-1,3-glycosidic backbone bearing a b-1,6-glycosidic branching every third residue of the main chain. Its physicochemical and biological properties make it attractive for different industries such as oil, chemical, pharmaceutical, cosmetic, foodand agricultural. This EPS can be obtained by submerged culture of selected Sclerotium strains with a proper production medium and adequate operative conditions. Currently, the possibilities for low-cost scleroglucan production are seriously examined. In this context, the use of alternative substrates or agro-industrial sub-products has attracted worldwide interest. In this work, EPS production by two selected Sclerotium rolfsii strains isolated from nature was comparatively assessed by using alternative substrates such as potato water extract and corn-derived industrial sub-products.Two different S. rolfsii strains, ATCC 201126 (isolated from rotten red pepper), and isolate 2745 (from rotten tomato) were grown in five different culture media. Production of EPS was tested by culturing in 250-mL Erlenmeyer flasks containing 50 mL of the following media: PMP [1] modified (in g/L: sucrose, 40; potato dextrose broth, 24; commercial corn steep liquor, 1), MLP [2] (containing 39g/Lglucose as C-source and 5 g/L (NH4)2SO4 as N-source), Potato I (in g/L: sucrose, 50; yeast extract, 1; potato water extract, q.s. 1 L), Potato II (in g/L: sucrose, 50; industrial corn steep liquor, 2.25; potato water extract, q.s. 1 L) and MOPT [3] as control medium (with 150 g/L sucrose as C-source and 2.25 g/L NaNO3 as N-source). Production of EPS was tested after cultivation at 30ºC and 250 rpm for 72 h. For every condition, EPS production and mycelial growth were measured by gravimetric estimation [3]. After EPS recovery by filtration, residual sugars were also determined in the filtrate by DNSA method [4].Both S. rolfsii strains showed ability to grow in all tested culture media. The highest EPS production was achieved in MOPT medium for both strains (strain 201126: 21.93 g/L,and strain 2745: 21.05 g/L), with no statistically significant differences (P>0.05). However, the lower growth obtained with the strain 201126 (12.61 g/L), than with the strain 2745 (18.45 g/L), denoted a higher specific productivity (Pr/x) of the former one. Based on the rheological characteristics of fermentation broth after 72 h of culture, a higher biomass concentration may represent a disadvantage for EPS recovery and this aspect may deserve a further evaluation. On the other hand, the use of alternative substrates derived from potato or corn industrial processing would be also viable for both strains since, though EPS concentration when using these media did not surpassed the values in MOPT, yields on C-source (Yp/c) were similar or higher. Likewise, the lower complexity of culture media with potato water extract (I and II) as compared to the other tested media reveals new possibilities for low-cost culture media formulation and its potential scaling-up.