Cheese Whey Fermentation Route for Food-Independent PLA Production
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Solution Overview
Problem
The dairy industry generates large amounts of cheese whey, which is a pollutant due to its high BOD and COD, and there is a need for an alternative raw material for producing polylactic acid (PLA) that does not compete with food resources like corn.
Innovation Solution
A process using bacterial fermentation of cheese whey to produce lactic acid, followed by ring-opening polymerization, utilizing SnCl2 as a catalyst and xylene as a solvent, to produce polylactic acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If corn is used as raw material for PLA production, then PLA production is achieved, but food resources are competed for
Solution Approach 1:
The patent changes the raw material parameter from corn (food source) to cheese whey (dairy waste), transforming the resource basis of PLA production. This parameter change resolves the contradiction by eliminating competition for food resources while maintaining PLA production capability through alternative feedstock utilization.
Solution Approach 2:
The patent converts cheese whey, which is considered waste and a pollutant due to its high BOD and COD, into a valuable raw material for PLA production. This transformation turns the harmful waste stream into a beneficial resource, simultaneously addressing both the PLA production need and the waste management challenge.
2Object-generated harmful factors
If cheese whey is discharged as waste, then pollution is avoided, but environmental harm increases due to high BOD and COD
Solution Approach 1:
The patent converts the harmful characteristics of cheese whey (high BOD and COD) into advantageous features for microbial fermentation. These same properties that cause pollution are utilized as nutrients for lactic acid bacteria, transforming the waste stream into a valuable carbon and nitrogen source for PLA production.
Solution Approach 2:
The patent enables the waste stream to serve itself by using its own nutritional content (proteins, lactose, fat) to support the fermentation process. The cheese whey provides both the carbon source and nitrogen source needed for lactic acid production, eliminating the need for external nutrient addition and turning the waste into a self-sufficient feedstock.
3Quantity of substance
If traditional PLA production methods are used, then PLA is produced, but sustainability is compromised due to corn dependency
Solution Approach 1:
The patent fundamentally changes the raw material parameter from corn-based to whey-based production. This parameter change addresses sustainability by eliminating dependency on food crops and utilizing instead a renewable waste stream from the dairy industry, thereby improving the environmental sustainability of the PLA production system.
Solution Approach 2:
The patent demonstrates the multi-functionality of cheese whey, which serves multiple purposes: it acts as a carbon source, nitrogen source, and energy source for the fermentation process. This universal utilization of a single waste stream enhances the sustainability and self-sufficiency of the production system.
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
This process effectively recovers lactic acid from cheese whey, producing PLA with chemical properties similar to commercial PLA, addressing the pollution issue and incorporating a domestic PLA production using dairy industry waste.
Implementation Method 1
bacterial fermentation of cheese whey to produce lactic acid
Implementation Method 2
fermentation of renewable sources
Implementation Method 3
ring-opening polymerization, utilizing SnCl2 as a catalyst
Implementation Method 4
utilizing SnCl2 as a catalyst
Implementation Method 5
xylene as a solvent
Implementation Method 6
Centrifuging the whey to discard precipitates and fats
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a process for producing polylactic acid (PLA), by means of bacterial fermentation using whey obtained from the production of cheese as the raw material, said process comprising at least the following steps: a) centrifuging the whey at 8000G for 10 minutes; b) quantifying the sugars and proteins; c) recording the density and pH; d) adding an inoculum of the strains Lactobacillus delbrueckii subsp bulgaricus and Streptococcus thermophilus in an approximate concentration of 75 mg L-1; e) anaerobically growing at 40 0C with stirring at between 200 - 500 rpm for 24 - 96 hours; f) identifying the lactic acid; and g) preparing the PLA, via isolation and purification processes, using physical-mechanical methods such as centrifugation and filtration. The invention also relates to the use of the process to valorize discarded whey from the cheese industry.