Enhanced production of pullulan by two strains of A. pullulans with different concentrations of soybean oil in sucrose solution in batch fermentations

Abstract

-Aureobasidium pullulans is a microorganism that produces pullulan (homopolysaccharide) extracellularly through a fermentation process with sugars (maltose, d-xylose, sucrose and starch) as its carbon source. Pullulan is a linear polysaccharide of D-glycopyranose containing (1 → 4)-α and (1 → 6)-α linkages at a 2:1 ratio, is highly soluble in water and has various applications in the food, packaging, film and pharmaceutical industries. Lipids, primarily oils, having antifoaming properties as well as nutritional particularities, are considered an essential additional carbon source for the growth of microorganisms, especially fungi. These nutrient sources are very important for the maintenance of microorganism cells. In fact, these positive effects are only achieved when the right source is added at both the right time and the right dosage into the broth of the fermentation process. In this research on pullulan production with the strains NRRL Y-6220 and NRRL Y-2311-1, it was found that the latter strain achieved better results for undesirable pigment formation, pullulan titer, time of maximum production (96 hours) and biomass yields than strain NRRL Y-6220, which also showed suitable results for biomass yields and cell morphology. However, the dark pigmentation of the strain NRRL Y-6220, formed through the process, makes its application unacceptable for foods and pharmaceuticals. Strain NRRL Y-2311-1 was shown to be a promising potential industrial microorganism, whose applications should be studied more in depth.

Production of pullulan by a thermotolerant Aureobasidium pullulans strain in non-stirred fed batch fermentation process

“…Besides other parameters in fermentation study stirred and non-stirred conditions are also important parameters which affect pullulan production during fermentation by A. pullulans (4,9,14).…”

“…Till now, mostly the production of pullulan was done at a temperature range of 24-32 o C only (3,4,7,9,11,14,17). This may suggest that the optimal temperature for pullulan production by A. pullulans vary from strain to strain.…”

“…(3,4,7,8,11,14,17). However, till to date no work has been reported for higher production of pullulan above 35 o C.…”

Downstream processing and characterization of pullulan from a novel colour variant strain of Aureobasidium pullulans FB-1

“…A number of investigations have reported pullulan precipitation using two volumes of ethanol (Kachhawa et al, 2003;Lazaridou, Roukas, Biliaderis, & Vaikousi, 2002). Sena, Costelli, Gibson, and Coughlin (2006) reported pullulan precipitation from the supernatant using one volume of 2-propanol per volume of supernatant. …”

Production of Pullulan from a high yielding strain of Aureobasidium pullulans in non-stirred flask-type fermentation system

“…Till date most of the studies have been reported on mesophilic strain of this fungus which produces pullulan up to level of 30-36 g/l in flask shake experiments or in fermentor experiments at a temperature range of 24-32 o C at different physico-chemical conditions (4,7,8,9,11,13,15,17). However, a high yielding strain of A. pullulans has not been reported so far which can also sustain a high temperature above 35 o C.…”