Software configurable radio with dynamic spectrum support is the inherent property of Cognitive radio. Interoperability of Cognitive radio with wireless sensor network would enable the sensor nodes to access and transmit the application data in licensed PU free channels. Since wireless sensor nodes operate in heavily crowded ISM bands (902 MHz/2.4 GHz), there will be severe performance degradation during channel saturation and increased collision rate. With opportunistic spectrum access, enhanced performance can be achieved by minimizing the channel access collisions and control message overhead delays. To achieve, this paper proposes a novel approach to integrate the sensor nodes with cognitive radio (CR) nodes to route sensor data to sink using licensed channels opportunistically. We further extend our novel approach to cluster sensor node and CR nodes to achieve energy efficiency. Simulation results show that the proposed solution with dynamic spectrum access enhances the throughput, minimizes energy consumption and reduces the delay compared with existing solutions.