# US 11,440,999 B2 · De-esterification of biomass prior to ammonia pretreatment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,999 B2 - Document ID: US11440999B2 - Status: Granted - Kind: B2 - Application number: 16/029,452 - Filed: 2018-07-06 - Published: 2019-01-10 - Granted: 2022-09-13 - Earliest claimed: 2017-07-07 - Assignees: Board of Trustees of Michigan State University - Applicants: Board of Trustees of Michigan State University - Inventors: Venkatesh Balan; Leonardo da Costa Sousa - Web page: https://patentgrep.com/patent/US11440999B2 ## CPC - C08H 8/00: Macromolecular compounds derived from lignocellulosic materials {(pretreatment thereof B27N)} - A23K 10/37: from waste material (from hydrolysates of wood or straw A23K10/32; from molasses A23K10/33) - A23K 10/38: from distillers' or brewers' waste - B01J 19/0006: {Controlling or regulating processes (controlling or regulating in general G05)} - C08H: DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS (polysaccharides C08B; natural rubber C08C; natural resins or their derivatives C09F; bituminous materials C10) - A23K: FODDER - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS ## Abstract 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. ## Claims ### Claim 1 A method of pretreating biomass comprising: de-esterifying the biomass with an alkali at a concentration from about 2% to 8% alkali in water, to cleave ester linkages to produce de-esterified biomass, wherein the alkali for the de-esterifying the biomass is Ca(OH)2 (lime), KOH, NaOH, or a combination thereof and wherein the alkali to biomass ratio is no greater than 40% (weight/weight); annealing the de-esterified biomass to reduce the moisture content of solids to less than about 30%; and without neutralizing the de-esterified biomass, pretreating the de-esterified biomass with ammonia to produce de-esterified ammonia pretreated biomass, wherein the ammonia to biomass ratio is between about 0.5:1 to about 1:1, the method resulting in an amide concentration range in the de-esterified ammonia pretreated biomass from substantially zero mg/g biomass to about 25 mg/g biomass. ### Claim 2 (depends on 1) The method of claim 1 wherein the amide concentration ranges from about 0.04 mg/g biomass to about 25 mg/g biomass. ### Claim 3 (depends on 1) The method of claim 1 wherein the pretreating biomass is pretreating densified biomass. ### Claim 4 (depends on 1) The method of claim 1 wherein the pretreating with ammonia reduces density in the de-esterified biomass to produce reduced-density biomass, and the method further includes re-densifying the reduced-density biomass following the pretreating with ammonia to produce animal feed. ### Claim 5 (depends on 1) The method of claim 1 wherein the pretreating step comprises a liquid ammonium hydroxide pretreatment or an ammonia fiber expansion (AFEX) pretreatment. ### Claim 6 (depends on 5) The method of claim 5 wherein the AFEX pretreatment is a liquid AFEX pretreatment, a gaseous AFEX pretreatment, or an extractive AFEX pretreatment. ### Claim 7 (depends on 1) The method of claim 1 wherein the biomass is brewer's spent grains (BSG) or distiller's dry grain DDGS. ### Claim 8 (depends on 1) The method of claim 1 wherein the biomass is lignocellulosic biomass. ### Claim 9 (depends on 8) The method of claim 8 wherein the lignocellulosic biomass is selected from corn stover, poplar, switchgrass, sugarcane bagasse, wheat straw, sorghum, energy cane, miscanthus, soybean meal, and combinations thereof. ### Claim 10 (depends on 8) The method of claim 8 wherein the pretreating step comprises a cellulosic conversion liquid ammonia pretreatment. ### Claim 11 (depends on 10) The method of claim 10 wherein the cellulosic conversion liquid ammonia pretreatment is a densified cellulosic conversion liquid ammonia pretreatment. ### Claim 12 (depends on 1) The method of claim 1 wherein the alkali is present in a concentration from 3% to about 8%. ### Claim 13 (depends on 1) The method of claim 1 wherein the alkali is present in a concentration from 3% to about 6%. ### Claim 14 A method of pretreating biomass comprising: de-esterifying the biomass with an alkali at a concentration from about 2% to 8% alkali in water, to cleave ester linkages to produce de-esterified biomass, wherein the alkali for the de-esterifying the biomass is Ca(OH)2 (lime), KOH, NaOH, or a combination thereof and wherein the alkali to biomass ratio is no greater than 40%, weight/weight; annealing the de-esterified biomass to reduce the moisture content to less than about 30%; and pretreating the de-esterified biomass with ammonia to produce de-esterified ammonia pretreated biomass, wherein the ammonia used in the pretreating step is reduced compared to an amount of ammonia used when pretreating biomass that has not been de-esterified, wherein the ammonia to biomass ratio is between about 0.5:1 to about 1:1, the method resulting in an amide concentration in the de-esterified ammonia pretreated biomass ranges from substantially zero mg/g biomass to about 25 mg/g biomass. ### Claim 15 (depends on 14) The method of claim 14 wherein the ammonia is reduced by up to 5% compared to the amount of ammonia used when pretreating biomass that has not been de-esterified. ### Claim 16 (depends on 14) The method of claim 14 wherein the de-esterified biomass is neutralized with concentrated hydrochloric acid or concentrated sulfuric acid prior to the pretreating the de-esterified biomass with ammonia step.