Disclosed are variants of Humicola grisea Cel7A, H. A plurality of first electrodes is provided on the first conductive semiconductor layer, and a second electrode electrically connects to the second conductive semiconductor layer. Floor brokers communicate with the trading system through handheld devices connected to a handheld server via a wireless interface. In one embodiment utilized for data transfers in the downstream direction, object download requests can be fulfilled by sending a sequence of partial download requests through the set of communication channels being aggregated, and forwarding the resulting partial data objects received to the original requester in the proper order.