No, the LED bulb will not light up. To light a bulb, we need to supply it electrical power, like the kind that an electrical wall outlet provides, or electrochemical power, like the chemical reaction that happens inside a battery. You might be able to include lemon juice in a chemical reaction, but by itself, it cannot react.

That's a fun experiment. You could try it. But batteries have a plus (+) and a minus (-) end with different chemical reactions at each end, so I think you would need something in addition to the lemon juice to make the LED light.

Here's a website that tells more about this :

lemon battery