Biomass De-esterification to Reduce Amide Formation
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Solution Overview
Problem
Conventional ammonia pretreatment methods for biomass conversion produce neurotoxic amides, such as acetamide, which require additional processing steps and consume more ammonia, increasing costs due to the reaction with acetyl and other ester linkages in plant cell walls.
Innovation Solution
An alkali de-esterification step is performed before ammonia pretreatment to cleave ester linkages, reducing or eliminating amide formation and ammonia consumption by using alkalis like sodium hydroxide or calcium hydroxide, thereby minimizing amide production and ammonia usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ammonia pretreatment is performed directly on biomass, then ammonia can penetrate and pretreat the biomass, but amides are formed which are neurotoxic and require additional processing steps
Solution Approach 1:
The patent applies preliminary de-esterification treatment to biomass before ammonia pretreatment. This preliminary action removes ester linkages from the biomass structure, preventing them from reacting with ammonia to form harmful amides during the subsequent ammonia pretreatment step, while still allowing ammonia to effectively penetrate and pretreat the biomass
2Reliability
If ammonia pretreatment is performed on biomass with ester linkages, then ammonia can pretreat the biomass, but ammonia is consumed in reactions with ester linkages increasing costs
Solution Approach 1:
The patent removes ester linkages through preliminary de-esterification treatment before ammonia pretreatment. This eliminates the chemical reaction between ammonia and ester linkages, preventing unnecessary ammonia consumption while maintaining the effectiveness of ammonia pretreatment for biomass modification
3Object-generated harmful factors
If additional processing steps are added to remove amides, then amide levels can be reduced, but process complexity and costs increase
Solution Approach 1:
The patent prevents amide formation in the first place by performing preliminary de-esterification to remove ester linkages before ammonia pretreatment. This proactive approach eliminates the need for subsequent amide removal steps, simplifying the overall process while effectively controlling amide levels in the final product
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 approach results in a pretreated biomass with significantly reduced amide levels, higher digestibility, and lower ammonia consumption, reducing processing costs and eliminating the need for additional amide removal steps, while maintaining the nutrient value and composition of the biomass.
Implementation Method 1
performing an alkali de-esterification step with an alkali to cleave ester linkages present in the biomass
Data Source
AI summary
A method is provided for pretreating cellulosic or lignocellulosic biomass comprising de-esterifying the biomass with an alkali treatment to produce de-esterified biomass; and pretreating the de-esterified biomass with ammonia to produce de-esterified ammonia pretreated biomass. In various embodiments, the de-esterified ammonia pretreated biomass has an amide concentration ranging from about 0.04 to about 25 mg/g biomass. In other embodiments, the amide concentration is no more than 0.04 mg/g biomass. Various ammonia pretreatment processes may be used, including liquid or gaseous ammonia pretreatments, including, but not limited to, liquid ammonium hydroxide pretreatments, various AFEX pretreatments, with or without biomass densification, and various cellulosic conversion pretreatments including “COBRA” pretreatments. Products (e.g., animal feed) and systems are also disclosed.