Production of Gellan Gum by Sphingomonas paucimobilis on Crude Sweet Whey Using Different Bioreactor Feeding Strategies
Rawia, F. Gamal
Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
Hemmat, M. Abdel-hady
Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
Shimaa, A. Amin *
Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
Shimaa, K. Ali
Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
*Author to whom correspondence should be addressed.
Abstract
Aims: Production of gellan gum by Sphingomoas paucimobilis from whey was optimized by different fermentation techniques.
Study Design: Study the growth behavior of Sphingomoas paucimobilis was cultivated on 40% sweet whey medium in the bioreactor as a batch, fed batch and continuous culture and effect of aeration and agitation speed on gellan production.
Place and Duration of Study: Microbiology Dept., Fac. of Agriculture, Ain Shams Univ., Cairo, Egypt, 2016/ 2017.
Methodology: Using Sphingomoas paucimobilis on sweet whey in the bioreactor as a batch, fed batch (pulsed & continuous) and continuous culture. Among the four levels of air saturation and four levels of agitation speeds.
Results: Using the continuous feeding of sugar sweet whey at 1.53 gl-1h-1during 12 h was favorable than pulsed feeding for gellan production in fed-batch culture. In continuous culture addition of 40% SW at 0.055 h-1 dilution rate (110 ml h-1), the values of gellan parameters recorded by Sphingomoas paucimobilis were 24.34%, 26.54% & 0.337 gl-1h-1 for gellan yield, conversion coefficient and gellan productivity during 24 h. At 28ºC. This technique increments the gellan production (gl-1h-1) by 3.3 & 2.2-2.5 and 1.5- 1.6 fold as compared to that produced by using batch & fed- batch pulsed and fed-batch continuous techniques respectively. The emulsifying capability of the partially purified gellan was 100% whereas it was 95% for xanthan gum, as well as its high flocculating activity than xanthan. A tough worm-like gel or firm gel were formed when 10% calcium chloride solution or 0.5 g sodium chloride were added to gellan solution.
Conclusion: The maximum gellan yield and lower fermentation period were obtained with air saturation of 60% at 750 rpm agitation speed. The continuous feeding at 1.53 gl-1h-1 was favorable than pulsed feeding for gellan production in fed-batch culture, while the maximum gellan productivity was obtained by using a continuous culture technique at 0.055 h-1 dilution rate.
Keywords: Gellan gum, Sphingomoas paucimobilis, batch culture, fed-batch, pulsed feeding, continuous feeding, continuous culture