Improving energy efficiency of Bacillus velezensis broth microfiltration in tubular ceramic membrane by air sparging and turbulence promoter

Abstract

BACKGROUND Popularity of biocontrol has increased due to the growing environmental concerns and the demand for organic products. It is considered as a sustainable practice for efficient agricultural production. Microbial biopesticides offer environment‐friendly biotechnological alternative to chemical control of plant diseases and pests. Due to its advantages in cell separation cross‐flow microfiltration has emerged as a powerful alternative to the conventional separation methods. However, the flux enhancement remains to be addressed. This study has estimated the use of flux improvement techniques for biomass harvesting by microfiltration using tubular ceramic membranes. Investigated methods for flux enhancement were turbulence promoter, i.e. Kenics static mixer, two‐phase flow (air sparging) and the combination of these two methods. RESULTS Significant flux improvement coincides with a reduction in specific energy consumption, while at the same time Bacillus velezensis cells have retained viability and antibacterial activity. The highest values of flux and corresponding improvement, compared to the microfiltration without enhancement techniques, are obtained in the case of combining Kenics static mixer and two‐phase flow (133.4 L m−2 h−1 and 502%). Flux improvement for air sparging was 134%, for turbulence promoter alone flux increase was 434%. CONCLUSION The methods proposed herein have achieved effective flux enhancement for cell harvesting. The obtained results also suggest encouraging basis to promote large‐scale economical production of biomass for biocontrol application. © 2019 Society of Chemical Industry

Dynamic Modeling Using Artificial Neural Network of Bacillus Velezensis Broth Cross-Flow Microfiltration Enhanced by Air-Sparging and Turbulence Promoter

“…The effective membrane length was 230 mm, with filtration area of 0.0043 m 2 . Apparatus used in microfiltration experiments was described by Jokić et al [16]. Recirculation of retentate and permeate in microfiltration experiments had assured constant feed conditions.…”

“…The reason for this can be found in the rapid flux decline at the beginning of Bacillus velezensis broth microfiltration. Cultivation broth is a complex mixture of various components that can cause severe membrane fouling in the initial phase of microfiltration [8,11,14,16]. This contributes to reduced ANN prediction capabilities in this region.…”

“…The Kenics static mixer causes the increase of feed velocity, hence the turbulence is caused by the unique flow pattern forming secondary flows and radial mixing which enable fluid movement closer to the membrane surface. This flow near the membrane surface increases permeate flux as it reduces the thickness of the cake layer and changes its brick like structure [16]. Furthermore, in the system with air sparging the presence of the turbulence promoter contributes to the significant change of a two-phase flow regimen by causing coalescence and bursting of the large air bubbles, as well as by making it possible for smaller air bubbles to flow near the membrane surface affecting breaking of the filtration cake structure, which lowers the permeate flow resistance leading to higher values of permeate flux and the steady state being reached faster.…”

“…The hydraulic resistance associated with the cake build-up is the main factor influencing the microfiltration of cultivation broths [8,11,12]. The reduction of cake layer, and consequently permeate flux improvement, can be achieved by applying flow alternations in a membrane channel [13][14][15][16][17].…”

Comparison of Polypropylene and Ceramic Microfiltration Membranes Applied for Separation of 1,3-PD Fermentation Broths and Saccharomyces cerevisiae Yeast Suspensions

“…Microfiltration (MF) is one of the oldest membrane technologies [ 1 ], which is characterized by operating pressure lower than 0.35 MPa and high permeate fluxes, mainly between 10 −4 and 10 −2 m/s [ 2 ]. Over the last two decades, many attempts have been made by researchers to comprehensively investigate the use of MF in the clarification of fermentation broths [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ] and yeast suspensions [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. It is due to the fact that separation of biological materials using conventional centrifugal methods is difficult and expensive [ 33 ].…”