LIPID ENHANCEMENT IN ALGAL BIOMASS USING MONOCHROMATIC OPTICAL FILTERS

Abstract

ABSTRACT The present invention relates to a method for enhancing lipid accumulation in algal biomass by utilizing monochromatic optical filters to selectively transmit specific wavelengths of light. The method involves culturing algae under controlled conditions, irradiating the culture with light filtered to selectively transmit blue (400-500 nm) and red (600-700 nm) wavelengths, which stimulate lipid biosynthesis and biomass growth, respectively. The system can adjust light intensity and duration based on the algae's growth phase, optimizing lipid production without significantly inhibiting biomass accumulation. Real-time monitoring sensors are used to track lipid accumulation, allowing for precise control over the light conditions. This method offers a sustainable, energy-efficient approach for increasing lipid yield in various algal species, including Chlorella, Nannochloropsis, Spirulina, and Haematococcus, making it suitable for biofuel production, nutraceuticals, and other industrial applications. The method significantly improves lipid content while maintaining high biomass productivity

Specification

Description:FIELD OF INVENTION
The present invention relates to the field of algal biotechnology, particularly to methods for enhancing lipid production in algal biomass. More specifically, the invention involves the use of monochromatic optical filters to optimize light wavelengths for improved lipid accumulation in algae cultures.

BACKGROUND OF THE INVENTION
Algae have gained significant attention in recent years as a sustainable and renewable source for biofuels, nutraceuticals, and high-value chemicals due to their rapid growth, ability to thrive in diverse environments, and high lipid content. Lipid accumulation in algae is particularly important for biofuel production, where algal lipids can be converted into biodiesel through transesterification. Several strategies have been employed to enhance lipid production in algae, including nutrient manipulation, genetic engineering, and light regulation.
Nutrient Starvation: One of the most common methods for enhancing lipid production is nutrient starvation, especially nitrogen depletion. Under nutrient stress, algae shift their metabolism from growth and protein synthesis to lipid accumulation as a survival mechanism. While effective in increasing lipid content, nutrient starvation typically results in a reduction in overall biomass yield, as the algae divert resources from cell division to lipid storage. This leads to lower overall productivity, limiting the efficiency of biofuel production.
Genetic Modification: Genetic engineering of algae has been explored as a means to increase lipid biosynthesis by altering key metabolic pathways. Techniques include overexpressing genes involved in fatty acid synthesis or downregulating genes responsible for competing pathways like carbohydrate production. Although genetic engineering holds promise, it comes with several challenges, such as high costs, public concerns over genetically modified organisms (GMOs), and regulatory hurdles. Additionally, genetic modification may result in unintended changes to the organism's physiology, potentially reducing its robustness and viability in large-scale operations.
Environmental Stress Induction: Applying environmental stresses, such as salinity, temperature fluctuations, and light intensity modulation, has been explored as a method to enhance lipid production in algae. Stress conditions trigger metabolic responses that promote lipid accumulation as a defense mechanism. However, the application of such stresses can also reduce overall algal growth, leading to decreased biomass productivity and operational inefficiencies.
Full-Spectrum Lighting Systems: In conventional algae cultivation systems, full-spectrum lighting, which includes all visible wavelengths of light, is commonly used to support photosynthesis and growth. Full-spectrum light simulates natural sunlight, but not all wavelengths are equally beneficial for algal lipid production. Some wavelengths favor cell growth rather than lipid biosynthesis, making full-spectrum lighting suboptimal for maximizing lipid yields. Additionally, these systems are energy-intensive and inefficient, as they fail to selectively target the wavelengths most effective for lipid enhancement.
Reduced Biomass Yield in Nutrient Starvation: While nutrient starvation is an effective technique to increase lipid content, it significantly reduces the overall biomass yield. The trade-off between lipid accumulation and cell growth limits the scalability of this approach for industrial applications. The decrease in algal biomass offsets the benefits of higher lipid content, resulting in lower overall lipid productivity.
Complexity and Risks of Genetic Engineering: Genetic modification of algae introduces complexities related to the stability of modified strains, regulatory barriers, and societal acceptance. Moreover, the metabolic changes induced by genetic engineering can negatively affect the algal growth rate and resilience, leading to operational challenges in maintaining consistent productivity at large scales. This makes the approach cost-prohibitive and unpredictable for commercial biofuel production.
Suboptimal Efficiency of Environmental Stress Methods: Environmental stress induction, though effective in enhancing lipid accumulation, comes with a significant drawback: it often stunts the overall growth of algae. Stressed algae may accumulate more lipids, but their slower growth rates result in reduced biomass production. This leads to an imbalance between the desired lipid output and the economic viability of the cultivation system, as the stress conditions are not conducive to large-scale, high-yield production.
Inefficiency of Full-Spectrum Lighting: Full-spectrum lighting systems are widely used in algal cultivation but are not optimized for lipid production. Since algae respond differently to various wavelengths of light, many of the wavelengths in full-spectrum lighting contribute more to photosynthesis and biomass accumulation than to lipid biosynthesis. This lack of wavelength selectivity leads to inefficient lipid production and higher energy consumption, making it a less sustainable option for large-scale cultivation.
Furthermore, full-spectrum lighting systems often require high energy input to produce light across the entire visible range, increasing operational costs. Since not all light wavelengths contribute equally to lipid production, much of this energy is wasted on wavelengths that do not enhance lipid accumulation, resulting in a costly and energy-inefficient process.
Therefore, there remains a need in the art for a method for enhancing lipid production in algal biomass using monochromatic optical filters that does not suffer from the above-mentioned deficiencies or at least provides a viable, economical and effective solution.
OBJECTS OF THE INVENTION
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can significantly enhance the lipid content in algal biomass by optimizing light quality through the use of monochromatic optical filters. This enables efficient lipid biosynthesis, making the process more viable for large-scale applications like biofuel production.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can reduce the energy consumption and operational costs associated with conventional lighting systems by using specific wavelengths of light that promote lipid production. The selective transmission of beneficial light spectra maximizes lipid yield while minimizing energy waste.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can reduce biomass growth.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can seeks to maintain or even enhance algal biomass productivity while increasing lipid accumulation to avoid trade-offs between growth and lipid content, thus maximizing total output.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can intended to be adaptable for various algal strains and growth setups, including photobioreactors and open pond systems. It is flexible enough to accommodate different species of algae, allowing for wide application across multiple industries, such as biofuels, nutraceuticals, and bioplastics.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can optimize the use of light by filtering and transmitting only the specific wavelengths that are most effective for lipid production in algae. By targeting red (600-700 nm) and blue (400-500 nm) light wavelengths, the system enhances lipid biosynthesis without unnecessary light exposure that primarily contributes to biomass growth.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can scalable for industrial applications, promoting large-scale lipid production in algae. By improving energy efficiency and lipid yields, it provides a more environmentally sustainable alternative to conventional methods, supporting cleaner energy initiatives and reducing dependence on fossil fuels.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can avoids the use of genetic engineering, chemical additives, or nutrient starvation, which can introduce complexity, regulatory hurdles, or operational inefficiencies. Instead, the system enhances lipid accumulation through non-invasive, environmentally friendly means, making it safer and easier to implement at scale.
An object of the present disclosure is to provide a method for enhancing lipid production in algal biomass using monochromatic optical filters that can integrate sensors and monitoring systems to continuously assess algal growth and lipid content, allowing for real-time adjustments to light conditions. This ensures optimal lipid production throughout the cultivation process, improving the overall efficiency and effectiveness.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
The present invention is generally directed to a method for enhancing lipid content in algal biomass through the use of monochromatic optical filters. These filters selectively transmit specific wavelengths of light that promote lipid biosynthesis while minimizing light spectra that may promote undesired metabolic pathways. The system is designed to be adaptable for different algal strains and growth conditions, making it versatile for various applications in biofuel production, nutraceuticals, and bioplastics.
The method involves cultivating algae under controlled light conditions using optical filters that transmit light in the desired monochromatic range, typically in the red and blue spectra. These specific wavelengths have been found to promote lipid accumulation by optimizing photosynthetic efficiency and triggering stress responses that lead to increased lipid biosynthesis.

DETAILED DESCRIPTION OF THE INVENTION
The following description is of exemplary embodiments only and is not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
The present invention provides a novel method to enhance lipid accumulation in algal biomass using monochromatic optical filters. By targeting specific light wavelengths, primarily in the blue (400-500 nm) and red (600-700 nm) spectrum, this method optimizes the photosynthetic and metabolic pathways in algae to produce higher lipid yields without compromising the overall biomass production. This approach eliminates the drawbacks of conventional methods such as nutrient starvation, genetic modification, and environmental stress, which often lead to reduced growth rates and biomass yield.
The method described here is not only energy-efficient but also adaptable for various types of algae and cultivation systems, including open ponds and photobioreactors. It allows for real-time monitoring of growth and lipid production, ensuring optimal light exposure throughout the algal growth cycle.
Step-by-Step Method:
Step 1: Selection and Preparation of Algal Species
1. Selection of Algal Strain: The method begins with selecting an appropriate algal strain known for its lipid production potential. Suitable species include:
• Chlorella vulgaris: Known for high lipid and biomass productivity.
• Nannochloropsis: A marine microalgae species with a high content of polyunsaturated fatty acids (PUFAs).
• Spirulina platensis: Cyanobacteria with moderate lipid production but significant biomass accumulation.
• Haematococcus pluvialis: Known for its capacity to produce high-value lipids and astaxanthin.
The choice of algae can be based on the desired end product, such as biodiesel, nutraceuticals, or pharmaceuticals.
2. Inoculation and Culture Preparation: Inoculate the selected algal strain into a suitable growth medium. Common media include:
• BG-11: For freshwater algae like Chlorella and Spirulina.
• F/2 medium: For marine species like Nannochloropsis.
• Modified Bold's Basal Medium (BBM): For a variety of algal species.
The starter culture is incubated under controlled conditions (temperature, pH, and salinity) to ensure optimal algal growth until the biomass reaches a sufficient density for further experimentation.
Step 2: Setup of the Cultivation Chamber and Monochromatic Lighting
1. Cultivation System Setup: The algae are transferred to the main cultivation system, which could be an open pond, photobioreactor, or closed vessel. This chamber is equipped with:
• Monochromatic Optical Filters: These filters are placed between the light source and the algae to selectively allow blue (400-500 nm) and red (600-700 nm) wavelengths to pass through, filtering out other wavelengths that are less effective or counterproductive for lipid production.
2. Light Source: The light source used is typically an LED array due to its energy efficiency and ability to provide consistent, controlled wavelengths. LEDs allow precise tuning of the light spectrum to ensure that only the targeted wavelengths are supplied to the algal culture.
3. Placement of Monochromatic Filters:
• Blue light (400-500 nm) primarily promotes photosynthesis and biomass growth during the early growth phase, driving higher energy production.
• Red light (600-700 nm) enhances the biosynthesis of lipids during later growth stages when algae begin to accumulate storage molecules like triacylglycerols (TAGs).
The filters are designed to either:
• Switch automatically based on the growth stage, or
• Maintain a fixed ratio of blue and red light depending on the species and desired lipid-to-biomass ratio.
4. Light Intensity and Duration: The intensity of light is adjusted in the range of 100-200 µmol/m²/s for both blue and red light. The duration of exposure is controlled using a photoperiod cycle of 12 hours of light and 12 hours of dark (or 16:8, depending on the algal strain), ensuring optimal light absorption and minimizing photo-inhibition.
Step 3: Cultivation and Real-Time Monitoring
1. Growth Phase:
o During the initial growth phase, algae are primarily exposed to blue light to stimulate photosynthetic activity and promote cell division.
o Monitoring sensors, including optical density (OD) sensors, are installed in the cultivation chamber to track biomass growth in real-time. Algal growth is continuously monitored, and adjustments to light intensity or nutrient levels are made as necessary.
2. Lipid Accumulation Phase: As the culture enters the lipid accumulation phase, usually after the exponential growth phase, the system gradually shifts the light spectrum to increase red light exposure. This stimulates the algae to switch from growth to lipid production pathways, enhancing the accumulation of storage lipids like TAGs.
o Nutrient stress, such as controlled nitrogen depletion, may be introduced during this phase to further enhance lipid production, although it is not necessary due to the optimized light conditions.
3. Real-Time Lipid Monitoring: Real-time lipid content monitoring can be achieved through sensors such as lipid-specific fluorescence probes or near-infrared (NIR) spectroscopy. These sensors provide feedback on lipid accumulation in the algae, allowing for real-time adjustments to the lighting conditions for optimal lipid yield.
Step 4: Harvesting Algal Biomass
1. Harvesting Time: The algae are harvested once the lipid content has reached the desired level, typically after 7-14 days of cultivation, depending on the species and growth conditions.
2. Separation and Extraction: The algal biomass is separated from the culture medium through methods such as centrifugation, filtration, or flocculation. The lipids are then extracted using solvent-based methods (e.g., hexane extraction) or more eco-friendly alternatives like supercritical CO2 extraction.
Step 5: Post-Harvest Analysis and Data Recording
1. Lipid Yield Analysis: The lipid content of the harvested biomass is quantified using methods such as gas chromatography (GC) or thin-layer chromatography (TLC). These methods provide detailed insights into the fatty acid profile and total lipid yield.
2. Data Logging: All experimental data, including growth rates, lipid accumulation, and light exposure conditions, are recorded in a centralized system for analysis. This data is critical for optimizing future experiments and scaling up the process for industrial applications.
Example Data Table:
The table below shows the experimental results of lipid accumulation in Chlorella vulgaris using the method described.
Parameter Control (Full-Spectrum Light) Monochromatic Filters (Blue + Red)
Light Intensity (µmol/m²/s) 150 150
Photoperiod (Light
) 12:12 12:12
CultivationDuration (Days) 14 14
Initial Biomass Concentration (g/L) 0.5 0.5
Final Biomass Concentration (g/L) 2.8 3.2
Lipid Content (% Dry Weight) 18.5 32.4
Lipid Yield (g/L) 0.52 1.03
Energy Consumption (kWh) 4.5 3.1
Discussion of Results:
• Increased Lipid Content: The use of monochromatic optical filters significantly increased lipid content in Chlorella vulgaris, as shown by the 32.4% lipid content in dry biomass compared to 18.5% under full-spectrum light.
• Improved Biomass Productivity: The overall biomass concentration in the monochromatic filter system was 3.2 g/L, higher than the 2.8 g/L in the control group, indicating that lipid enhancement did not compromise growth.
• Energy Efficiency: The system using monochromatic filters consumed 31% less energy than the full-spectrum lighting system due to the selective targeting of wavelengths, reducing unnecessary energy expenditure.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. , Claims:We Claim,
1. A method for enhancing lipid accumulation in algal biomass, comprising the steps of:
culturing algae in a cultivation chamber under controlled conditions;
irradiating the algae with light filtered through a monochromatic optical filter system, wherein the filter selectively transmits wavelengths in the blue (400-500 nm) and red (600-700 nm) spectra;
optimizing the light exposure to promote lipid biosynthesis without significantly inhibiting algal biomass growth;
harvesting the algal biomass with increased lipid content.
2. The method as claimed in claim 1, further comprising the step of adjusting the intensity and duration of the transmitted light to enhance lipid production at different growth stages of the algae.
3. The method as claimed in claim 1, wherein the algae are exposed to the monochromatic light for a specific duration that maximizes lipid biosynthesis without the need for nutrient deprivation or environmental stress induction.
4. The method as claimed in claim 1, wherein the cultivation chamber includes sensors that monitor lipid accumulation in real-time, allowing for adjustments to the light intensity and wavelength for optimal lipid enhancement.
5. The method as claimed in claim 1, wherein the algae used in the cultivation chamber are selected from a group consisting of Chlorella, Nannochloropsis, Spirulina, and Haematococcus species.

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