Mutant Rhizopus oryzae Strain for Simultaneous Saccharification and Fermentation
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Solution Overview
Problem
Commercial production of fumaric acid through microbial fermentation is hindered by high raw material costs and low yield when using traditional processes with cheap starch as a substrate, necessitating the development of strains with enhanced glucoamylase activity to facilitate simultaneous saccharification and fermentation.
Innovation Solution
A mutant Rhizopus oryzae strain, ME-F13, is developed through nitrogen ion implantation mutagenesis and screening with 2-Deoxyglucose resistance, exhibiting significantly increased glucoamylase activity, allowing for fumaric acid production from starch materials via simultaneous saccharification and fermentation without additional glucoamylase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional fermentation processes use cheap starch as raw material, then raw material cost is low, but fumaric acid yield is quite low
Solution Approach 1:
The patent applies parameter changes by mutating the Rhizopus oryzae strain to alter its enzymatic parameters, specifically increasing glucoamylase activity. This genetic modification enables the microorganism to efficiently convert starch to glucose and then to fumaric acid, resolving the contradiction between using cheap starch and achieving high yield.
Solution Approach 2:
The patent replaces the need for separate mechanical saccharification equipment with a biologically-based system. The mutated Rhizopus oryzae strain performs both saccharification (breaking down starch to glucose) and fermentation (converting glucose to fumaric acid) in a single biological process, eliminating the need for additional equipment and process steps.
2Productivity
If separate saccharification and fermentation processes are used, then process control is easier, but equipment cost and fermentation time increase
Solution Approach 1:
The patent merges two separate processes (saccharification and fermentation) into a single simultaneous operation called SSF (Simultaneous Saccharification and Fermentation). The mutated Rhizopus oryzae strain performs both functions concurrently, reducing equipment requirements and fermentation time while maintaining process control.
Solution Approach 2:
The mutated Rhizopus oryzae strain exhibits multi-functionality by simultaneously performing saccharification (starch breakdown) and fermentation (fumaric acid production). This universal organism replaces what would traditionally require separate specialized systems, reducing overall device complexity and cost.
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
The mutant strain achieves a 2.5-fold increase in glucoamylase activity and 28% higher fumaric acid yield, reducing substrate inhibition and fermentation time, and lowering equipment costs, offering improved industrial prospects.
Implementation Method 1
The original strain of Rhizopus oryzae ME-F12 (ME-UN-8) was mutagenized by nitrogen ion implantation, to obtain the mutant strain.
Implementation Method 2
If the glucoamylase activity of Rhizopus oryzae can be increased, fumaric acid can be produced by simultaneously saccharifying starchy material and fermenting it
Implementation Method 3
This mutant features a significantly increased glucoamylase activity, about 2.5 times that of the original strain, and therefore it can be used to produce fumaric acid with starchy materials through the SSF process
Data Source
AI summary
A rhizopus oryzae strain, mutagenesis and screening methods thereof, and methods of producing fumaric acid by fermentation. The strain is named as Rhizopus oryzae ME-F13, and deposited in China Center for Type Culture Collection with depository number CCTCC M 2010351. The strain is obtained by physically mutagenizing the original strain ME-F12 through ion injection, culturing the processed bacteria on the solid selective plate containing 2-D-deoxylucose (2-DG) and picking up 2-DG-resistant single colony. The strain is capable of simultaneously saccharifying starchy material and fermenting it to produce fumaric acid. With an improved enzymatic activity, the strain can be directly used to ferment raw starchy materials without needing pre-saccharifying.