Recent Patents on Chemical Engineering - Volume 3, Issue 2, 2010

Ultrasounds, an efficient and virtually innocuous means of activation in synthetic chemistry, have been employed for decades with varied success. This high-energy input enhances not only mechanical effects in heterogeneous processes, but it is also known to induce new reactivities leading to the formation of unexpected chemical species. The remarkable phenomenon of cavitation makes sonochemistry unique. This patent review is aimed at summarizing the status of cavitational chemistry in organic synthesis and to highlight the more recent applications in this field. The use of ultrasound to promote chemical reactions is called sonochemistry. The effects of ultrasound observed during organic reactions are due to cavitation, a physical process that creates, enlarges, and implodes gaseous and vaporous cavities in an irradiated liquid. Cavitation induces very high local temperatures and pressures inside the bubbles (cavities), leading to turbulent flow of the liquid and enhanced mass transfer.

Large amounts of waste are generated during production, distribution, and consumption of any product. Over the past three decades, efforts have been made to minimize waste through source reduction, reuse, and treatment in order to achieve cleaner production and prevent pollution. This review summarizes patents related to treatment methods for waste minimization in different industrial sectors that were issued during the last 29 years. Online database maintained by the United States Patents and Trademark Office (USPTO) was searched for this review. The patents were obtained from the USPTO database using the search criterion, by entering the sector name and using the keywords as waste minimization or treatment in the “title and abstracts.” The review provided an overview of various waste minimization techniques for industries, hospitals, biosolids, construction, and agriculture. Also, it provided insight into the developments in reduction of waste over the years. The basic principle in these developments and research are the three R's in the waste hierarchy: reduce, reuse, and recycle. The patents cover new treatment and disposal processes. The majority of the patents related to waste minimization were found in the industrial, biosolids, and hospital sectors. A trend study on the number of patents issued related to waste minimization techniques in the above sectors showed a gradual increase from 1977 and peaked between 1993 and 2004, and decreased in recent years. The review showed that the research efforts and rapid development of patents associated with the five sectors were predominant between 1993 and 2004.

Due to the unique properties exhibited by carbon nanotubes, the explorations on its potential applications are ongoing. Among them, carbon nanotube seems to open a door for solving some problems encountered by current separation materials. The aim of the present contribution is to review recent patent developments of carbon nanotube (CNT) applications in separation including membrane-based separation and adsorption separation reported in the open literatures, especially in current patents. And, the corresponding advantages and disadvantages resulting from the employment of carbon nanotube for separation were also discussed and compared. Furthermore, some future research directions in this field were also put forward tentatively.

For many years protein hydrolysates have been used in the food industry due to ability to modify the functional properties of proteins, mainly solubility, emulsifying and foaming features, flavour, etc. More recently, protein hydrolysates are incorporated as food ingredients in energy-providing drinks, hypoallergenic formulae, enteral diets for children and clinical nutrition. To this end, the nutritional properties are improved in comparison with native proteins. Among the various protein sources (soy, wheat, egg, haemoglobin, etc.) whey proteins are outstanding due to their high nutritional value, low bitterness (depending on the enzymatic process) and low antigenicity. Finally, whey protein hydrolysates constitute an excellent source of bioactive peptides, showing anti-hypertensive, immunological or antimicrobial activity, for instance. With respect to the manufacturing of whey protein hydrolysates, the enzymatic bioconversion processes are of increasing use in the production, transformation and valorisation of protein raw materials. Predominantly, industrial production is carried out in a classical batch reactor at controlled temperature. At the end of the reaction the enzyme is inactivated and remains into the final product. However, there are several disadvantages associated to this method, the high enzyme consumption being the main one. Hence, alternative operational procedures have been proposed, mainly enzyme immobilisation onto supports and the use of ultrafiltration membranes. Thus, membrane ultrafiltration of whey protein hydrolysate is aimed at: i) fractionating the hydrolysate in order to adjust its functional and nutritional properties, ii) remove the enzyme from the final hydrolysate and iii) recover and reuse the enzyme in further reactions if possible. Whey protein hydrolysates have received much attention after the Second World War (SWW). Patents dealing with whey protein hydrolysates have been issued regularly, particularly during the 1970s. Initially, the scope of such patents was to produce whey protein hydrolysates as food modifiers (improving protein solubility, providing emulsifying or foaming ability, etc.). During the 1980s and 1990s, patents were focused on reducing the antigenicity of proteins. For this purpose, it is essential to control the characteristics of the final hydrolysate. Hence, membrane technologies were used to obtain selected fractions and remove undesirable substances like free amino acids or non-reacted native proteins. Finally, selected peptides released during enzymatic degradation of proteins may regulate biological processes like hypertension mechanisms, immune reactions, etc. Thus, the manufacturing of bioactive peptides is a new research area and a number of recent patents have been published. In this article, a comprehensive review of the patents dealing with the enzymatic processes, membrane technologies and applications of whey protein hydrolysates is provided.

Sedimentation is a natural phenomenon on which the most frequent unit operations using relative flow of macrofluids are based. Its most significant applications in process engineering have separative purposes, often in the field of wastewater conditioning and treatment. Knowledge of settling mechanisms and the reliable design of high-performance, flexible settlers are two objectives seldom achieved. Many of the advances in theoretical knowledge do not automatically imply relevant achievements in practice in treatment plants. So, the best way to identify the main operative problems is by examining the areas in which inventors are claiming their patents. This article deals with the advances developed in recent years in this field. The related patents were first subjected to thorough individual analysis and later classified into three categories: study of the phenomenon itself, improvements in design and applications.

Complex medical devices like endoscopes are very difficult to sterilize, due to the use of different materials for their construction and to complex device geometries that are difficult to process using liquid sterilants. The use of materials like metals, polymers and glasses requires the adoption of sterilization techniques characterized by reduced thermal and mechanical energy. In this work patents on medical devices sterilization have been reported. Then, we focused our attention on the fact that structured surfaces formed by micro- or nano- spaces suggest the use of gas-like processes characterized by reduced surface tension and improved mass transfer, like the supercritical fluids. Therefore, patented techniques based on the use of supercritical CO2 (SC-CO2) have been studied, indicating the possible mechanism of microorganism inactivation; then, due to some limitations of SC-CO2 action, the addition of small quantities of other compounds, like carboxylic acids, hydrogen peroxide and in general oxidative or non-oxidative additives, has been patented. These approaches have been reviewed, together with a new sterilization concept based on the modification of acetic and peracetic acid by the addition of SC-CO2, producing expanded liquid single phase mixtures, whose action can be modulated for the sterilization of micro-structured and delicate medical instruments.

The fish and aquaculture activities produce an important volume of by-products due to discards and processing on board and in land. These residues (fillet cuts, bones, heads, viscera and tails) require to be processed in order to not create a significant environmental problem and to maintain the economical viability of the fisheries sector. The present paper reviews a list of recent patents on fish by-products applications, specifically on the products with the highest added value, such as fish protein hydrolysates and fish oil. Initially, an assessment is presented of the processes and techniques employed to obtain fish protein hydrolysates, which are classified by their utilization: ingredients for food, products for animal feeding, bioactive compounds, fertilizers, cosmetics and nutrient media for bacterial growth in specific industrial processes. Secondly, the different methods to extract the oil from the fish, to refine the fish oil avoiding undesirable taste and odour and to improve the stability of the mentioned oil, are evaluated. Finally, procedures for the microencapsulation of the oil obtained and its incorporation into food compositions have been surveyed.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by different chemicals, raw materials, materials, machines, design methods, chemical processes and techniques involved and related to chemical engineering.