Disinfectant supplier Tristel posted a rise in turnover and profits in the six months to December 31 as it proceeded with the integration of a portfolio of products it acquired from Medichem.Pre-tax profits climbed to £656,000 from £469,000 over the same period the previous year as revenues climbed to £4.03m from £3.15m.The acquisition of the Medichem portfolio of disinfectant products, which was acquired on July 3, contributed £594,000 to first half turnover, the company said.A reduction in gross margins to 63.1% from 65.1% was due to the acquisition, but the company expects this to improve in the second half as the transition of manufacturing of the products continues. About 65% of the blending and packing of the portfolio had been taken over by Tristel by December and the remainder will be manufactured in house during the second half, Tristel said.Overseas sales increased by 20% during the period said Tristel, whose aim is to develop the business internationally. Tristel has exposure to the US through a licensing agreement with Clorox, an S&P 500 company that makes bleach and other cleaning products. It is also registering its products in emerging markets such as Russia and China.The interim dividend rises by 5% from a year ago to 0.425p.