Packed-Bed Cider Fermentation for Continuous Vinegar Production
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Solution Overview
Problem
There is a need for new methods of producing apple cider vinegar in a continuous process and suitable beds for such production, as existing batch methods are inefficient and limited.
Innovation Solution
A method involving a tubular bioreactor filled with a porous bed made from carbon-apple extrudates, using a countercurrent flow of nutrient solution and oxygen, and employing Acetobacter bacteria for continuous fermentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch methods are used to produce apple cider vinegar with large surface area exposure to oxygen, then acetic fermentation can occur, but the process is inefficient and limited in productivity
Solution Approach 1:
The patent implements a continuous acetic fermentation process where apple cider continuously flows through a packed bed bioreactor containing immobilized Acetobacter bacteria. This continuous operation eliminates the periodic filling and emptying of batch vessels, maintaining constant fermentation activity and significantly improving acetic acid productivity compared to traditional batch methods
Solution Approach 2:
The patent uses a packed bed bioreactor filled with porous support material that provides large surface area for Acetobacter bacteria immobilization. The porous structure increases the available surface area for oxygen transfer and bacterial attachment, enhancing fermentation efficiency while maintaining a simple reactor design
2Productivity
If traditional batch methods with coarsely cut oak chips are used to increase surface area, then sensory characteristics are improved, but the process remains batch-based with low productivity
Solution Approach 1:
The invention transitions from periodic batch processing to continuous fermentation operation. Apple cider is continuously pumped through the bioreactor, allowing uninterrupted acetic acid production. The system maintains steady-state operation with continuous substrate input and product output, dramatically increasing fermentation efficiency and productivity
Solution Approach 2:
The patent changes the fundamental operational parameter from batch to continuous mode. Additionally, it immobilizes Acetobacter bacteria on solid support material, changing the biological state from free-floating to attached growth. These parameter changes enable sustained high-rate fermentation while maintaining process flexibility through adjustable flow rates
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
Enables the production of apple cider vinegar in a continuous process with increased fermentation dynamics and efficiency, achieving high acetic acid productivity and quality.
Implementation Method 1
acetic fermentation process, which is an oxidation process of ethanol catalysed by aerobic Acetobacter bacteria
Implementation Method 2
acetic fermentation process, which is an oxidation process of ethanol catalysed by aerobic Acetobacter bacteria
Implementation Method 3
a bed consisting of a porous material, such as carbon-apple extrudate
Data Source
Figure 1~2
AI summary
The object of the present invention is a method of producing acetic acid by acetic fermentation, wherein the fermentation medium, which is cider containing 5.2 % w/w ethanol and 20 g/dm3 glucose, is fed from above into a tubular bioreactor at a volume rate of 30 cm3 /h, using a retention time of 66.6 h for the fermentation medium in the reactor; oxygen is fed from the bottom of the bioreactor at a pressure of 110 000 Pa and a volume intensity of 480 cm3/h; characterised in that the tubular bioreactor is filled with a porous bed obtained by a method comprising the steps of: (a) the apple pomace shall be vacuum dried at a temperature of 40 to 80°C, preferably 50 to 70°C, more preferably at 60°C and under pressure of 60 000Pa to give a product with a moisture content of 40%; (b) the material obtained is subjected to further drying, preferably in a convection dryer, at a temperature of 100 to 110°C, preferably 105°C, until a product with a moisture content of 20% is obtained; (c) the apple pomace with a moisture content of 20% is mixed with charcoal, preferably apple charcoal, silicon oxide, calcium carbonate and calcium sulphate and crushed, followed by the addition of an aqueous glass solution and the whole is mixed, the quantities of the individual components being as follows: apple pomace with a moisture content of 20% (61.82%), charcoal (30.91%), silicon oxide SiO2 (0.46%), aqueous glass, solution of 10% by weight in water (6.18%), calcium carbonate anhydrous (0.31%), calcium sulphate anhydrous (0.31%); (d) the resulting mass is extruded in an extruder operating at a screw speed of 200 rpm, a compression ratio of 1.75 and a heating power of 2kW to produce extrudates with a diameter of 20-30 mm, preferably 25 mm; (e) extrudates are allowed to rest for 24 h; whereby, prior to the acetic fermentation process, the bed is subjected to conditioning, in which the extrudates are crushed, washed with distilled water at room temperature, and poured over a solution of the following composition: water (62.28%), apple juice (31.14%), ethanol 70% v/v (6.23%), magnesium sulphate (VI) (0.05%), lyophilised cultures of Acetobacter (0.31%); and left for 48 h using a pure oxygen flow rate of 10 ml/min.