Evaluation of pullulan production by a newly isolated Micrococcus luteus

Pullulan is one of the most essential exopolysachharides (EPS) of α(Glucan) units in which most commonly α(1→4) linkage predominate. The Aureobasidium pullulans is the key microorganism for pullulan production. A major problem with Aureobasidium pullulans is coproduction of melanin along with pullulan. In this study, we looked for a novel strain having potential to produce pullulan without producing melanin and to evaluate various process parameters for its production. A total of 20 isolates were obtained from the soil sample but out of these only one strain that produced a significant amount of pullulan (71.39 mg/mL). This strain was identified as Micrococcus luteus (GenBank accession no KX261689) based upon the 16S rRNA sequencing. The characterization of pullulan was done with Enzymatic (Pullulanase) hydrolysis study and FTIR analysis. More than 85% hydrolysis of pullulan by pullulanase enzyme had also indicated the presence of α(1→6) and α(1→4) linkages in the structure of pullulan. Various evaluated values of different parameters for production of pullulan were found to be pH: 6.0, Temperature:35˚C, rpm: 250, Incubation time: 5 days. A Central Composite Design (CCD) was implemented in which peptone showed more effect than other factors in pullulan elaboration.

The role of microbial pullulan, a biopolymer in pharmaceutical approaches: A review.

The article presents an overview of the latest advances in investigations and application of the pullulan from microbes (Auriobasidium sps.) and its derivatives in the biomedical and pharmaceutical field and how this polysaccharide can be of use as a promising biomaterial in the coming future. So many papers were published during the last four decades indicated that pullulan the unique biomaterial which has so many applications in food, cosmetics, biomedical and pharmaceutical industries . The unique linkage α (1→4) and α (1→6) pattern of pullulan endows the polymer with distinctive physical traits, including adhesive properties and the capacity to form fibers. Due to its non-toxic, non-immunogenic, non-mutagenic and non-carcinogenic nature recently there is an attempt to explore this polysaccharide for various medical applications including targeted drug and gene delivery, tissue engineering, wound healing and also even in diagnostic applications like perfusion, receptor, and lymph node target specific imaging and vascular compartment imaging using it as quantum dots.