Electromagnetic biostimulation of living cultures for biotechnology, biofuel and bioenergy applications

Abstract

The surge of interest in bioenergy has been marked with increasing efforts in research and development to identify new sources of biomass and to incorporate cutting-edge biotechnology to improve efficiency and increase yields. It is evident that various microorganisms will play an integral role in the development of this newly emerging industry, such as yeast for ethanol and Escherichia coli for fine chemical fermentation. However, it appears that microalgae have become the most promising prospect for biomass production due to their ability to grow fast, produce large quantities of lipids, carbohydrates and proteins, thrive in poor quality waters, sequester and recycle carbon dioxide from industrial flue gases and remove pollutants from industrial, agricultural and municipal wastewaters. In an attempt to better understand and manipulate microorganisms for optimum production capacity, many researchers have investigated alternative methods for stimulating their growth and metabolic behavior. One such novel approach is the use of electromagnetic fields for the stimulation of growth and metabolic cascades and controlling biochemical pathways. An effort has been made in this review to consolidate the information on the current status of biostimulation research to enhance microbial growth and metabolism using electromagnetic fields. It summarizes information on the biostimulatory effects on growth and other biological processes to obtain insight regarding factors and dosages that lead to the stimulation and also what kind of processes have been reportedly affected. Diverse mechanistic theories and explanations for biological effects of electromagnetic fields on intra and extracellular environment have been discussed. The foundations of biophysical interactions such as bioelectromagnetic and biophotonic communication and organization within living systems are expounded with special consideration for spatiotemporal aspects of electromagnetic topology, leading to the potential of multipolar electromagnetic systems. The future direction for the use of biostimulation using bioelectromagnetic, biophotonic and electrochemical methods have been proposed for biotechnology industries in general with emphasis on an holistic biofuel system encompassing production of algal biomass, its processing and conversion to biofuel.

Keywords: algae; bioenergy; biofuels; biomass; biostimulation; electromagnetic field; growth; metabolism; multipolar.

Figure 1.

Overview of various electromagnetic stimulation modalities from fields and waves.

Figure 2.

Cross-section of a test tube and a 6-polar electrode configuration for biostimulation of E.coli.

Figure 3.

Maximum growth increase, achieved in E. coli cultures in test tubes versus frequency of the 6-polar AC EMF treatment (right vertical axis). The left vertical axis shows time to achieve the maximum, while the right axis shows concentration increase with respect to the control.

Figure 4.

Concept map of an EMF biostimulation at different levels of living systems.

Figure 5.

Molecular interaction sites of electromagnetic influences.

1. Cell Membrane

   1. - Magnetic field oscillations may increase membrane permeability under ion cyclotron resonance

   2. - Increased circulation and selective enhancement of ion flow may affect the rate of biochemical reactions

   3. - Alter the rate of binding of calcium ions to enzymes or receptor sites

   4. - Change distribution of protein and lipid domains, and conformational changes in lipid-protein associations

   5. - Change internal molecular distribution of electronic charge inside lipid molecule in the membrane bilayer

   6. - May play the primary role in the stochastic resonance amplification process

2. Chloroplast

   1. - May modulate the quantity of pigments, such as chlorophyll, phycocyanin, and beta-carotene

3. Nucleus/DNA

   1. - Magnetic field affects specific gene expression

   2. - Individual DNA sequences may function as antennae

   3. - Leads to changes in DNA conformation

   4. - May activate different DNA sequences depending on field intensity

   5. - Can affect enzyme activity

4. Proteins:

   1. - Breathing motions are the source and receiver of multipole EMF

   2. - Potential coupling mechanism for external multipolar influences

5. Protoplasm

   1. - Static magnetic fields influence the speed of protoplasm movement, miotic activity, and quantity of organic acids in plants

6. Whole Cell

   1. - Biophotonic emission and interaction with nearby cells

   2. - Endogenous electric field modulation may alter natural processes

Figure 6.

Integrated biostimulation/biofuel production system.

Figure 7.

Bioengineering of algae cultivation.