[Shohreh]

As a quick solution, I downloaded the trialware of Adobe Acrobat Pro DC, and manually removed all occurences of the offending string — Unless I missed it, that application doesn't seem to have a search+replace feature.

I'll keep investigating, though, since it could come handy.

For some reason, PyPDF2 fails finding the string:

#pip install PyPDF2
import PyPDF2, re

INPUTFILE = "input.pdf"
String = "Offending string"

object = PyPDF2.PdfFileReader(INPUTFILE)

NumPages = object.getNumPages()
for i in range(0, NumPages):
	PageObj = object.getPage(i)
	print("this is page " + str(i)) 
	Text = PageObj.extractText() 
	ResSearch = re.search(String, Text)
	print(ResSearch)