Fermentation at non-conventional conditions in food- and bio-sciences by the application of advanced processing technologies

Abstract

The interest in improving the yield and productivity values of relevant microbial fermentations is an increasingly important issue for the scientific community. Therefore, several strategies have been tested for the stimulation of microbial growth and manipulation of their metabolic behavior. One promising approach involves the performance of fermentative processes during non-conventional conditions, which includes high pressure (HP), electric fields (EF) and ultrasound (US). These advanced technologies are usually applied for microbial inactivation in the context of food processing. However, the approach described in this study focuses on the use of these technologies at sub-lethal levels, since the aim is microbial growth and fermentation under these stress conditions. During these sub-lethal conditions, microbial strains develop specific genetic, physiologic and metabolic stress responses, possibly leading to fermentation products and processes with novel characteristics. In some cases, these modifications can represent considerable improvements, such as increased yields, productivities and fermentation rates, lower accumulation of by-products and/or production of different compounds. Although several studies report the successful application of these technologies during the fermentation processes, information on this subject is still scarce and poorly understood. For that reason, the present review paper intends to assemble and discuss the main findings reported in the literature to date, and aims to stimulate interest and encourage further developments in this field.

Keywords:

• High pressure
• electric fields
• PEF
• MEF
• ohmic heating
• ultrasound
• sub-lethal
• microorganisms

Disclosure statement

FCT/MEC for the financial support to the QOPNA research Unit (FCT UID/QUI/00062/2013), through national funds and where applicable co-financed by the FEDER, within the PT2020 Partnership Agreement. Authors Maria J. Mota and Rita P. Lopes thank FCT for the grants SFRH/BD/97061/2013 and SFRH/BD/97062/2013, respectively. Shahin Roohinejad would like to acknowledge the Alexander von Humboldt Foundation, Germany, for his postdoctoral research fellowship.

Additional information

Funding

FCT/MEC for the financial support to the QOPNA research Unit (FCT UID/QUI/00062/2013), through national funds and where applicable co-financed by the FEDER, within the PT2020 Partnership Agreement. Authors Maria J. Mota and Rita P. Lopes thank FCT for the grants SFRH/BD/97061/2013 and SFRH/BD/97062/2013, respectively. Shahin Roohinejad would like to acknowledge the Alexander von Humboldt Foundation, Germany, for his postdoctoral research fellowship.