1. A computer-readable non-transitory medium encoded with a workflow application comprising modules executable by a processor and configured to process a plurality of work items in a workflow, the workflow application comprising: a queue storage module to receive a plurality of work items from a remote computer and to store each of the plurality of work items in one of a plurality of queues based on a state of each work item in the workflow; a queue selection module to determine a retrieval priority for each of the plurality of queues and to retrieve at least one work item from each of the plurality of queues according to the retrieval priority for storage in a workflow data structure; and an adaptive processing module to selectively adjust a number of processing modules each configured to process work items stored in the workflow data structure by: activating at least one processing module when an actual processing load is greater than a maximum threshold load level; and deactivating at least one processing module when the actual processing load is less than a minimum threshold load level, wherein the maximum threshold load level is ninety percent (90%) of a maximum processing capacity and the minimum threshold load level is twenty-five percent (25%) of processing capacity.