Leaf　protein　can　be　extracted　cost-efficiently　using　0.1　mol　dm(-3)　NaOH,　but　this　process　is　less　sustainable　due　to　the　generation　of　large　amounts　of　sodium　salts.　KOH　or　Ca(OH)(2)　are　considered　as　replacements　for　NaOH,　as　these　salts　can　be　reused.　This　work　evaluates　the　economic　and　environmental　sustainability　of　weak　alkaline　pectin　extraction　followed　by　KOH　enhanced　protein　extraction,　and　Viscozyme((R))　L-aided　pectin　extraction　followed　by　Ca(OH)(2)　enhanced　protein　extraction.　The　evaluations　are　made　for　green　tea　residue　and　are　compared　to　related　processes　using　NaOH.　The　predicted　profits　using　KOH　are　comparable　to　those　using　NaOH.　Environmental　sustainability　improves　for　all　impact　categories　in　the　case　of　KOH　extraction.　Further　environmental　benefits　are　obtained　by　substituting　conventional　K　fertilizer　with　the　K-rich　salty　waste　water　from　the　extraction　process.　The　profits　of　the　process　using　Ca(OH)(2)　are　highly　dependent　on　the　extraction　yield　of　the　protein　product.　Protein　extraction　yields　using　Ca(OH)(2)　need　to　be　higher　than　70%　to　be　more　profitable　than　the　same　process　with　NaOH.　The　environmental　benefits　of　Ca(OH)(2)　extraction　include　the　absence　of　salty　waste　water　and　the　net　production　of　heat.　This　is　accompanied　by　increased　electricity　consumption.　Thus,　the　impact　categories　of　climate　change,　fossil　and　water　depletion,　and　particulate　matter　formation　worsen.　Photochemical　oxidant　formations　remain　the　same,　while　the　other　impacts　improve.　This　work　has　shown　the　potential　and　bottlenecks　of　NaOH,　KOH　and　Ca(OH)(2)　protein　extraction　on　different　types　of　biomass　in　terms　of　environmental　and　economic　sustainability.　(c)　2018　Society　of　Chemical　Industry　and　John　Wiley　&　Sons,　Ltd