Sed command not working based on variable

Question

I am having problems in execution a sepefic sed command.

I have a bunch of files which will be target to several "find and replace" via sed.

In the file_test there is the following text example:

*FILENAME TESTE "DIR1.PGM1";*

My desired output is:

*FILENAME TESTE "/NEW_ROOT/DIR1.PGM1";*

The following command works:

*sed -i -e '/FILENAME/s!"!"/NEW_ROOT/!' file_test*

However having several alterations to make I opted to list the on a file a loop through it. list_changes FILENAME /NEW_ROOT/

Below its the logic I've implemented:

*#!/bin/bash
diretoria=pasta_b
ficheiro=teste
arquivo_2="$2" # serve para guardar o nome do txt
  while read -r linha; do
   grep_input=$(echo "$linha" | cut -d "    " -f 1) #get input for sed
   grep_output=$(echo "$linha" | cut -d "   " -f 2) #get output for sed
   
   cd ~/Desktop/FUENTES/"$diretoria"
   
   novo_fich="novo_$ficheiro" #rename file  
   cat "$ficheiro" >> "$novo_fich".txt #rename file  
   
   comand_sed="sed -i -e '/"$grep_input'/s!"!"/'$grep_output"/!' "$novo_fich".txt"
   echo "Comando : $comand_sed"
   
  call_comand=$(${comand_sed})
   
  cd ~/Desktop/FUENTES/   
done < "$arquivo_2"*

The error it gives is the following:

sed: -e expression #1, char 1: unknown command: `''

However the command_sed variable outputs to a well constructed sed command:

 sed -i -e '/LIBNAME/s!"!"/2sasdata2/!' novo_base08.txt

To sum up, my issue is giving a command based on a previously assigned variable (comand_sed)