MICROFILTRATION AND ULTRAFILTRATION OF Bacillus thuringiensis FERMENTATION BROTH: MEMBRANE PERFORMANCE AND SPORE-CRYSTAL RECOVERY APPROACHES

Abstract

-Recovery of spores and crystals from the fermentation broth of Bacillus thuringiensis (Bt) was studied using the membrane separation technology. Four types of polymeric membranes, with different characteristics, in the range of microfiltration (MF) and ultrafiltration (UF) were used for evaluating their permeate flux and spore-crystal recovery capacity. Results indicated that both MF and UF membranes are effective for spore-crystal recovery. The hydrophobic MF membrane made of polyvinylidene fluoride (PVDF) achieved a better performance compared to the one made with hydrophilic cellulose acetate (CA). Both had a 0.22 µm pore size, under the condition of an upper range of feed pressure. Also, with the increase of the feed flow rate, a higher flux was achieved for the PVDF membrane. A UF membrane made of polyethersulfone (PES) polymer was also used effectively for spore/crystal recovery from the broth, but under a higher operating pressure. In the entire experiment, a 99.9% rejection factor was measured with the applied membranes for the spore/crystal in the fermentation broth.

Modeling and Optimization of Gas Sparging-Assisted Bacterial Cultivation Broth Microfiltration by Response Surface Methodology and Genetic Algorithm

“…Therefore, numerous flux enhancement methods have been developed and experimentally investigated in recent years. Physical or chemical feed-mixture pretreatment together with appropriate choice of membrane material could prevent membrane fouling and contribute to increased permeate flux values, as showed in case of microfiltration of Bacillus thuringiensis cultivation broth [ 22 , 23 ]. Different flow manipulations could be applied in order to enhance mass transfer near membrane surface, including application of static turbulence promoters [ 18 , 24 , 25 , 26 ] and feed flow alterations, such as pulsing, back-flushing, vibration, etc.…”

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

“…The high effectiveness of NaOH solution is related to the fact that at caustic conditions, large organic particles (e.g., colloids and microbes) can be disintegrated into fine particles and soluble organic matters, while organic matters (e.g., proteins and carbohydrates) can be hydrolyzed and solubilized into small molecules [ 78 ]. It is worth noting that in the study [ 10 ], NaOH solution was successfully used as a cleaning agent for microfiltration membranes made of CA and PVDF and a PES ultrafiltration membrane fouled with Bacillus thuringiensis fermentation broth.…”

“…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 ].…”

Advances in Membrane Technologies

“…All modifications have targeted more efficient clearance of uremic toxins and controlling body originated mediators Introductory Chapter: An Overview of Recent Advances in Membrane Technologies DOI: http://dx.doi.org/10.5772/intechopen.89552 as a result of defensive system activations. Currently, medium cut-off membranes (60 kDa) are candidates of higher performance with acceptable clearance and low nutrient loss [73,102]. After many years of development, zwitterionized membranes are most recent generation of hemocompatible dialyzers [96][97][98][99].…”