Bacillus Fermentation Partial Harvest for Higher Protein Yield
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Solution Overview
Problem
Existing large-scale industrial fermentation processes for producing proteins using Bacillus host cells face challenges in maximizing yield, despite variations in media composition and carbon feeding rates.
Innovation Solution
A method involving inoculating a fermentation medium with Bacillus host cells containing an expression construct, cultivating under conducive conditions with a carbon source feed solution, and separating portions at different time points to obtain the protein of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carbon source is fed at constant or varying amounts during cultivation, then Bacillus cells grow and express protein of interest, but protein yield is not maximized
Solution Approach 1:
The patent applies dynamics by transitioning from static carbon source feeding (constant rates) to dynamic feeding strategies. Specifically, it uses increasing carbon source addition rates during exponential growth phase to match cellular uptake capacity, then switches to decreasing rates during stationary phase to maintain protein expression while preventing substrate inhibition. This dynamic adjustment optimizes both growth and protein yield without excessive process complexity.
Solution Approach 2:
The patent implements parameter changes by systematically varying carbon source concentration, addition rate, and timing throughout the fermentation process. Key parameter transitions include: initial carbon source concentration optimization, switching from constant to increasing addition rates during growth phase, then to decreasing rates during production phase. These parameter changes directly address the contradiction by maximizing protein yield through precise control rather than simple constant feeding.
2Productivity
If cultivation continues in large-scale bioreactors, then biomass increases, but protein yield per unit time decreases due to substrate depletion and metabolic shifts
Solution Approach 1:
The patent applies periodic action through staged carbon source feeding with distinct phases: an initial phase with moderate feeding, followed by an increasing rate phase during exponential growth, then a decreasing rate phase during stationary phase. This periodic modulation of carbon supply timing and rate prevents substrate depletion issues while maintaining high protein yield per unit time throughout extended cultivation.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining optimal carbon source availability throughout the entire cultivation duration. Through continuous monitoring and adjusted feeding strategies, the system prevents metabolic shifts associated with substrate depletion while sustaining protein expression. This continuous optimization allows extended cultivation without the typical yield decline seen in conventional batch processes.
3Productivity
If carbon feeding rate is increased to enhance growth rate, then biomass production increases, but specific substrate uptake rate becomes limiting
Solution Approach 1:
The patent resolves this contradiction through dynamic carbon feeding adjustment. During exponential growth phase, the system implements increasing carbon source addition rates that track with cellular growth and substrate uptake capacity. This dynamic approach ensures the specific substrate uptake rate remains reliable and non-limiting throughout rapid biomass accumulation, preventing the bottleneck that occurs with constant high-rate feeding.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances protein yield by optimizing cultivation phases and separation strategies, suitable for both laboratory and industrial scales.
Implementation Method 1
The biotechnological production of the product of interest is conducted via fermentation and subsequent purification of the product. Microorganisms, like the Bacillus species, are capable of secreting significant amounts of product into the fermentation broth.
Data Source
AI summary
The present invention relates to the field of industrial fermentation. In particular, it relates to method for producing a protein of interest from a Bacillus host cell comprising the steps of inoculating a fermentation medium with a Bacillus host cell comprising an expression construct for a gene encoding a protein of interest, cultivating the Bacillus host cell in said fermentation medium under conditions conducive for the growth of the Bacillus host cell and the expression of the protein of interest for a cultivation phase, wherein the cultivation of the Bacillus host cell during said cultivation phase comprises the addition of at least one feed solution and wherein the at least one feed solution provides a carbon source, and separating portions from said Bacillus host cell culture during the cultivation phase at different time points and obtaining the protein of interest from said portions.