As a retail investor I want to apply more then Rs 1 lakhs in an IPO. Can I invest in Non-institutional bidder's category? If yes then what are advantages or disadvantages of this?

Yes, a retail individual investor can bid for more then Rs 1 Lakhs in an IPO by applying in 'Non Institutional Investors' category. There is no upper limit for bidding amount in 'Non Institutional Investors' category.

Advantage:

You can apply for more then Rs 1 Lakhs and may get much better allocation then a retail bidder.

Disadvantage: 

Non-institutional bidders have an allocation of 15% of shares of the total issue size in Book Build IPO's, while retail Individual investors has 35% (remaining 50% is for QIB's).  As Non-institutional category has much smaller in size, issue usually oversubscribed much higher (then in retail category) and less shares allocation.