How can I isolate glycolic acid from sugarcane juice?
Ethylene Glycol was not used as a catalyst! Kataoka described in 2001 the production of Glycolic acid (GA) from ethylene glycol using glycol-oxidizing microorganisms isolated from soil, which is what the author of this thesis is trying to say (the writing is unclear though). It will be difficult to reproduce this in your home since you would need to cultivate those microorganisms inside your own house, chemical oxidation would also be a problem if you mean to use it for medical purposes (the oxidation of ethylene glycol releases formaldehyde, which is toxic and probably carcinogenic), besides the reaction needs potassium dichromate to happen which is also hazardous.

Fruits produce a small amount of glycolic acid and you can try to extract it from banana or sugarcane pulp by an acid-base workup, though I believe you won't get much pure GA using this method (specially if you don't have a deep knowledge of organic chemistry).

Glycolic acid is very easy to find online and it will be a lot cheaper to buy it from ebay or other source then to synthesize it if your goal is to use it for its skin effects.

Source: Glycolic Acid Production Using Ethylene Glycol-Oxidizing Microorganisms
Michihiko KATAOKA, Mié SASAKI, Aklani-Rose G.D. HIDALGO, Michiko NAKANO &amp; Sakayu SHIMIZU
Bioscience, Biotechnology, and Biochemistry Vol. 65 , Iss. 10,2001