NOVELTY - A biomass to alcohol production system comprises at least one ultrasonic energy transducer (100); and a biomass to alcohol production facility, associated with the ultrasonic energy transducer. The biomass to alcohol production facility is preferably a plant biomass to ethanol production facility.    USE - As a system useful for converting biomass (e.g. plant biomass including agricultural crop wastes and residues) to alcohol such as ethanol; and useful in production of alcohols including but not limited to industrial alcohols such as methanol, ethanol, isopropanol, butanol and propanediol that is used for making bioplastics.    ADVANTAGE - The system improves biomass conversion to alcohol, in a cost-effective manner, using ultrasonic energy produced by the ultrasonic energy transducer. The biomass to alcohol production system employs ultrasonic energy for pretreatment of biomass slurry. The ultrasonic energy applied to the biomass slurry, increases conversion rates of components (e.g. cellulose, hemicellulose) in biomass slurry to fermentable sugars. The use of ultrasonic energy for biomass pre-treatment, produces highly digestible cellulose solids that can achieve high glucose yields with low enzyme loadings, resulting in lower cellulase costs; eliminates the need for acid during pretreatment, while generating high sugar yields; reduces/eliminates the need for chemicals during pretreatment and pre-fermentation conditioning, thus lowering the cost of materials of construction because of a less corrosive environment, and minimizing the formation of degraded sugars and subsequent production of chemicals such as furfural, which inhibits microbial fermentation; reduces heat and energy demands, further minimizing the formation of degraded sugars and subsequent production of chemicals such as furfural; creates low water usage due to highly-effective destructuring and disaggregation of hemicellulose, cellulose and lignin; and optimizes settings in flowrate, temperature and acid level, to maximize hemicellulose recovery and lignin removal with water or dilute acid solutions in flow-through reactor systems. In addition, the ultrasonic energy when used after fermentation, decreases the presence of unwanted genetically-engineered materials in the product and waste streams (e.g. feed molasses stream), thus reducing the material amounts to undetectable levels. The biomass to alcohol production system increases overall yields of alcohol, such as ethanol, by at least 10 (preferably more than 100)%. The ultrasonic transducer can be interfaced with or integrated into existing processing steps and technologies, thus allowing ethanol producers to overcome technological hurdles, inefficiencies and poor yields, in an easy and cost-efficient manner, without the need to undergo costly and time-consuming re-tooling of facilities. High powered ultrasonic (HPU) energy can be applied at various points in the process of producing alcohol from biomass. As a result, economic barriers that are currently preventing the commercial implementation of biomass conversion technologies, are reduced or eliminated. The systems utilizes ultrasonic energy at frequencies and intensities required on an industrial scale, to reduce the production cost of ethanol, by improving biomass conversion per ton, reducing processing times for higher throughput, reducing operating costs, and increasing the marketability of co-products. Thus, the use of ultrasonic energy increases the efficiency of biomass conversion; increases the efficiency of alcohol production; and provides improvement in marketable by-products and/or production of marketable by-products.    DESCRIPTION OF DRAWING(S) - The figure shows a simplified, schematic view of an ultrasonic transducer located in a process flow stream.    Ultrasonic energy transducer (100)    Moving fluid medium of a biomass to alcohol production facility (102)    Large particulates of fluid medium (104)    Ultrasonic energy (106)    Horn of ultrasonic energy transducer (108)    Small particulates broken down from large particulates. (110)