Can Suzuki Gixxer 155cc start with the start button without using clutch when it is in neutral?

Yes, you can

The Suzuki Gixxer starts without the use of clutch when in neutral. The bike starts in any gear with the clutch operation with the start button also. It is powered by a 155 cc engine, producing 14.6 BHP and 14 NM of torque. The bike comes in two avatars, a naked one and a fully faired one. Both the bikes are excellent performers in their respective segments, making up a good duo against Yamaha FZ and Fazer series. They have a 266 mm disc brake for the front and the rear tyre has a 130 mm drum brake. The tyre sizes being used are the same in both the bikes, making them only different from the fairing point of view. All the Gixxer's come with a kick for emergency conditions. The price range varies from INR 72,199 to INR 84,939.

Suzuki Gixxer Series - Gixxer 155, Gixxer SF & Gixxer SF MotoGP Edition