ReviewA review of applications of cavitation in biochemical engineering/biotechnology
Introduction
The process industry demands that operations be performed in the most efficient way with respect to either product quality, energy or time, or in terms of economics. Alternative novel technologies are constantly being sought to reduce the total processing cost while maintaining or enhancing product quality in an environmentally benign manner. Cavitation offers immense potential for intensification of physical or chemical processing in an energy-efficient manner. Cavitation is generally defined as the generation, subsequent growth and collapse of cavities, resulting in very high local energy densities [1]. Cavitation, when it occurs in a reactor, generates conditions of very high temperatures and pressures (100–5000 atmospheres of pressure and 500–15000 K of temperature) locally, but with the overall environment remaining equivalent to ambient atmospheric conditions [1]. This enables the effective execution under ambient conditions of the various physical processes or chemical reactions that require stringent conditions [2], [3]. Moreover, free radicals are generated in the process due to the dissociation of vapors trapped in the cavitating bubbles, which results in either intensification of the chemical reactions or in alteration of reaction mechanism. Cavitation also results in the generation of local turbulence and liquid micro-circulation (acoustic streaming) in the reactor, enhancing the rates of transport processes; in addition, they also eliminate mass transfer resistances in heterogeneous systems [2]. Based on the degree of intensity, which may be described in terms of the magnitude of pressure or temperature, cavitation can also be classified as either transient or stable. The energy requirements for the generation of these two types are significantly different, and hence proper care must be taken when selecting the operating parameters for the specific type of application [4]. Transient cavitation is a process where the generated bubble/cavity will eventually collapse to a minute fraction of its original size, at which point the gas present within the bubble dissipates into the surrounding liquid via a rather violent mechanism, releasing a significant amount of energy in the form of an acoustic shock-wave and as visible light. At the point of total collapse, the temperature of the vapor within the bubble may be several thousand Kelvin, and the pressure may be several hundred atmospheres. In the case of stable or non-inertial cavitation, small bubbles in a liquid are forced to oscillate in size or shape due to some form of energy input, such as an acoustic field, when the intensity of the energy input is insufficient to cause total bubble collapse. This form of cavitation causes significantly milder cavitational effects than the transient cavitation.
Cavitation is also classified into four types based on the mode of generation: acoustic, hydrodynamic, optic and particle. Only acoustic and hydrodynamic cavitation have been found to be efficient in producing the desired chemical/physical changes in processing applications [2], [5], whereas optic and particle cavitation are typically used for single bubble cavitation, which fails to induce any physical or chemical change in the bulk solution. The spectacular effects of cavitation phenomena generated using ultrasound (acoustic cavitation) have been more commonly harnessed in food and bioprocessing industries [6]. Similar cavitation phenomena can also be generated relatively easily in hydraulic systems. Engineers have generally been cautious regarding cavitation in hydraulic devices due to the problems of mechanical erosion, and thus all initial efforts to understand it were mainly with the objective of suppressing it in order to avoid the erosion of exposed surfaces. However, a careful design of the system allows for generation of cavity collapse conditions similar to acoustic cavitation. This enables different applications requiring varying cavitational intensities that have been successfully carried out using acoustic cavitation phenomena but with much lower energy input as compared to sonochemical reactors. In the last decade, concentrated efforts were made by few researchers around the world to harness the spectacular effects of hydrodynamic cavitation for chemical/physical transformation [7]. The present work provides an overview of different applications of cavitational reactors with an emphasis on different operations in biochemical engineering/biotechnology.
Section snippets
Reactor designs
Reactors in which cavitation is generated by ultrasound are usually described as sonochemical reactors, whereas reactors in which cavities are generated by virtue of fluid energy are described as hydrodynamic cavitation reactors.
Microbial cell disruption
A key factor in the economical production of industrially important microbial components is an efficient large-scale cell disruption process [16], [17]. The need for an efficient microbial cell disruption operation has always hindered the large-scale production of commercial biotechnological products of intracellular derivation [16]. For the large-scale disruption of micro-organisms, mechanical disintegrators such as high-speed agitator bead mills and high-pressure homogenizers are commonly
Concluding remarks
The present work has enabled us to clearly exemplify the importance of cavitation phenomena generated by using both ultrasound and hydrodynamic means in the general area of biotechnology/biochemical engineering. Generally it has been observed that the mechanical effects are more dominant in these applications as compared to the chemical effects of cavitation phenomena. The efficacy of hydrodynamic cavitation is well established as compared to ultrasound generated cavitation, especially in
References (101)
- et al.
Mapping the efficacy of new designs for large scale sonochemical reactors
Ultrason. Sonochem.
(2007) - et al.
Some aspects of the design of sonochemical reactors
Ultrason. Sonochem.
(2003) - et al.
Conceptual design of a novel hydrodynamic cavitation reactor
Chem. Eng. Sci.
(2007) - et al.
Methods for disruption of microbial cells for potential use in the dairy industry—a review
Int. Dairy J.
(2002) - et al.
Microbial cell disruption: role of cavitation
Chem. Eng. J.
(1994) - et al.
Use of hydrodynamic cavitation for large scale cell disruption
Trans. Inst. Chem. Eng. Part C
(1997) - et al.
Selective release of invertase by hydrodynamic cavitation
Biochem. Eng. J.
(2001) - et al.
Disruption of microbial cells for intracellular products
Enz. Microb. Technol.
(1986) - et al.
Heat induced translocation of proteins and enzymes within the cells: an effective way to optimize the microbial cell disruption process
Biochem. Eng. J.
(2005) - et al.
Improved cavitational cell disruption following pH pretreatment for the extraction of β-galactosidase from Kluveromyces lactis
Biochem. Eng. J.
(2006)
The effect of chemical pretreatment combined with mechanical disruption on the extent of disruption and release of intracellular protein from E. coli
Biochem. Eng. J.
Potential uses of ultrasound in the biological decontamination of water
Ultrason. Sonochem.
The development and evaluation of ultrasound in the biocidal treatment of water
Ultrason. Sonochem.
Inactivation of microbes using ultrasound: a review
Int. J. Food Microbiol.
Water disinfection by acoustic and hydrodynamic cavitation
Biochem. Eng. J.
Ultrasound pre-treatment for enhanced biodegradability of the distillery wastewater
Ultrason. Sonochem.
Ultrasound and ozone assisted biological degradation of thermally pretreated and anaerobically pretreated distillery wastewater
Chemosphere
Solubilisation of waste-activated sludge by ultrasonic treatment
Chem. Eng. J.
Ultrasonic disintegration of biosolids for improved biodegradation
Ultrason. Sonochem.
The use of ultrasound to accelerate the anaerobic digestion of sewage sludge
Water Sci. Technol.
Treatment of dairy wastewater with two-stage anaerobic sequencing batch reactor systems: thermophilic versus mesophilic operations
Bioresour. Technol.
Improvement of biological activity by low energy ultrasound assisted bioreactors
Ultrasonics
Using acoustic cavitation to improve the bio-activity of activated sludge
Bioresour. Technol.
Ultrasound-assisted crystallization (sonocrystallization)
Ultrason. Sonochem.
Crystallization of potash alum: effect of power ultrasound
Ultrason. Sonochem.
Rapid lactose recovery from paneer whey using sonocrystallization: a process optimization
Chem. Eng. Proc.
Effect of ultrasound on anti-solvent crystallization process
J. Crystal Growth
Effect of ultrasound on the induction time and the metastable zone widths of potassium sulphate
Chem. Eng. J.
The application of power ultrasound to reaction crystallization
Ultrason. Sonochem.
Biodiesel production from waste cooking oil: process design and technological assessment
Bioresour. Technol.
Cavitational reactors for process intensification of chemical processing applications: a critical review
Chem. Eng. Proc.
Preparation of biodiesel with the help of ultrasonic and hydrodynamic cavitation
Ultrasonics
Fatty acid methyl esters from vegetable oil by means of ultrasonic energy
Ultrason. Sonochem.
Ultrasonic versus silent methylation of vegetable oils
Ultrason. Sonochem.
Conversion of sewage sludge into lipids by Lipomyces starkeyi for biodiesel production
Bioresour. Technol.
Ultrasound emulsification: effect of ultrasonic and physicochemical properties on dispersed phase volume and droplet size
Ultrason. Sonochem.
A study on the emulsification of oil by power ultrasound
Ultrason. Sonochem.
Emulsification by ultrasound: drop size distribution and stability
Ultrason. Sonochem.
The use of ultrasonics for nanoemulsion preparation
Innovative Food Sci. Emerg. Technol.
Investigation in solid–liquid extraction: influence of ultrasound
Chem. Eng. J.
An overview of ultrasonically assisted extraction of bioactive principles from herbs
Ultrason. Sonochem.
Ultrasound-assisted extraction of hesperidin from Penggan (Citrus reticulata) peel
Ultrason. Sonochem.
Ultrasound-assisted extraction of rutin and quercetin from Euonymus alatus (Thunb.) Sieb
Ultrason. Sonochem.
Optimization of ultrasound extraction of phenolic compounds from coconut (Cocos nucifera) shell powder by response surface methodology
Ultrason. Sonochem.
Ultrasonic extraction of oil from tobacco (Nicotiana tabacum L.) seeds
Ultrason. Sonochem.
Improved extraction of vegetable oils under high-intensity ultrasound and/or microwaves
Ultrason. Sonochem.
Comparison of conventional and ultrasound-assisted extraction of phenolics-rich heteroxylans from wheat bran
Ultrason. Sonochem.
Ultrasound-assisted extraction of capsaicinoids from Capsicum frutescens on a lab- and pilot-plant scale
Ultrason. Sonochem.
Effect of power ultrasound on freezing rate during immersion freezing
J. Food Eng.
Microstructural change of potato tissues frozen by ultrasound-assisted immersion freezing
J. Food Eng.
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