Patent Protection of Microorganisms with Special Reference to Ferrous-Iron and Sulfur Oxidizing Bacteria

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1 BIOTECHNOLOGY ND BIOENGINEERING VOL. XVII (1975) Patent Protection of Microorganisms with Special Reference to Ferrous-Iron and Sulfur Oxidizing Bacteria INTRODUCTION The protection of inventions by patents is an important part of any industrial research and development program. In industrial microbiology, the impact of progress is reflected by an increasing number of patents which feature the use of microorganisms in fermentations and other biological processes. s the industrial exploitation of a variety of microorganisms is becoming more intensive and widely appreciated, it is important to improve the standards of patent practice relating to these microorganisms. In this study, the patents which apply to ferrous-iron and sulfur oxidizing thiobacilli are reviewed in relation to the principles and rulings of the current patent practice. SOME PROBLEMS OF PTENT PRCTICE RELTING TO INDUSTRIL MICROORGNISMS The basic prin~iplesl-~ of patent protection which also apply to microorganisms may be briefly summarized as follows. 1) patent does not necessarily grant to its owner the sole right of exploitation of the invention but it does prevent its industrial exploitation by others without compensation. 2) The patent rights only apply to the processes and methods which are clearly defined and verified in the patent issue. 3) patent issue must contain complete disclosure of the invention to enable an expert ( skilled worker in the art ) to reproduce the featured process or method without involving further research work. 4) patent may be extended to apply to any process or method which results in the same product provided that it concerns a novel invention not previously described in the scientific literature..these principles also implement the basic ruling on patent claims which feature the use of industrial microorganisms in biotechnology. lthough the patent legislation varies in different countrie~,~ some remarks can be made on problems relating to legal and scientific controversies on the use of industrially important microorganisms. It seems that many litigations involving infringement of patent rights may arise from the interpretation of the inadequate definition, identification, and Classification of patented microorganisms. This problem is particularly acute in the pharmaceutical industry, which employs highly productive strains of microorganisms often produced by selection and mutation. In many countries it is now obligatory to deposit the patent culture in a recognized culture collection prior to filing the patent application.*p6 The availability of such cultures is restricted to authorized requests until the patent application has been approved by the Patent Office. However, the culture collections do not usually check on the proposed classification, identity, and properties of the 1975 by John Wiley & Sons, Inc

2 1854 BIOTECHNOLOGY ND BIOENGINEERING VOL. XVII (1975) cultures. Indeed, they only serve as a culture bank and source of deposited cultures. There appears to be no control over the possible changes in the deposited culture resulting from new information on their identity and characteristics or from mutations taking place during storage. Further confusion is evoked by the variable ruling on the natural and artificially produced mutants which may sometimes be assumed in the patent description. Some criticism has already been expressed on the standards currently accepted for patenting industrially important rnicroorganism~.~.~*~ More precise standards are clearly required for the unambiguous identity description, definition, and classification of patent cultures. n important requirement for a successful patent application is that the invention be not published or otherwise disclosed to public view prior to its filing. Some exemptions to this ruling exist as outlined previously.2.4 This ruling implies, however, that prior publications may invalidate the novelty of the invention and may therefore result in the rejection of the application. It is also clear that, once a patent has been issued, the patent rights-even if not industrially or economically practicable-may subject other later applications to a possible infringement and thus conserve the economic and industrial potential of the invention. The current patent practice indicates that microorganisms previously described in the scientific literature together with their well-established reactions cannot be protected by patents. Thus, the validity of many patents which feature industrial microorganisms may well be in doubt because of disclosures which lack novel information and are in any event well known facts in the literature. THIOBCILLI IN METLLURGICL INDUSTRY It is well established that autotrophic iron and sulfur oxidizing bacteria can be employed in metallurgy to oxidize metal sulfides and to regenerate ferric sulfate solutions for the acid leaching of metals from ores. Evidently, it is the combined action of the bacteria, ferric iron, and sulfuric acid that can be used most effectively to solubilize sulfide minerals although there is also some evidence to show that bacteria can act as the sole leaching agent by oxidizing solid sulfides to sulfate in acid conditions. The most successful results have been obtained with Thiobacillus fettooxiduns, which oxidizes ferrous-iron and reduced inorganic sulfur compounds such as metal sulfides and elemental sulfur, as the sole source of energy for growth. Other thiobacilli have also been shown to contribute to this leaching but their use may be more limited since they lack the capacity of oxidizing ferrous-iron. Mixed populations of thiobacilli occur in ore leaching deposits; thus 2'. thiooxidans may develop with T. ferrooxidans on a mixed sulfur-pyrite medium and T. concretivorus and T. thioparus, which have a requirement for higher ph values, can also thrive together. The results for the microbiological leaching of ores obtained with thiobacilli under laboratory conditions and in pilot-plant scale have clearly indicated their value in metallurgical processes. The microbiological leaching of ores is particularly useful for the treatment of low-grade ores and mining waste materials since the current physicochemical methods would be uneconomical. nother interesting application is the oxidation of ferrous sulfate by T. fettooxidans to ferric iron which by chemical action can be used to release uranium and other metals from their ores. Some refineries produce ferrous sulfate as a bulk waste

3 COMMUNICTIONS TO THK KI)ITOlt product and its oxidation to ferric sulfate by T. ferrooxidans could be envisaged for use, for example, in sewage purification as an alternative flocculant to aluminum salts. It is clear that by their controlled use these microbiological processes could also reduce the harmful effects of environmental pollution resulting from heavy metals and acidic mine drainage waters. Some microbiological processes have already been applied to ore leaching in the mining indust,ry and several patents have been granted for the use of thiobacilli (7'. ferrooxidans) for the production of ferric and other soluble heavy metal sulfates from ore materials. PTENTS RELTING TO THIOBCILLI Examples of patents for the use of iron and sulfur oxidizing thiobacilli in metallurgical processes are listed in Table I. The patents usually include descriptions of experiments which indicate the bacterial action relevant to the industrial processes. It is apparent, however, that the experimental details are often incomplete and inadequate to unequivocally establish the microbiological reactions involved. Some experiments describe the effect of various factors such as 02- and C0,-tension, nutrients, temperature, ph, and metal ions on the bacterial processes. Such information, however, has already appeared in TBLE I Examples of Patents Relating to the Use of Thiobacilli in Metallurgical Processes - Country Patent no. Year of issue Microorganismsa U.S.. ustralia U.S.. U.S.. U.S.. U.S.. Great Britain U.S.. U.S.. U.S.. U.S.. Great Britain U.S.. Japan U.S.. Germany (FRG) Czechoslovakia Czechoslovakia U.S.. 2,829, , ,.552 3,218, ,701 3,260,593 3,266,889 3,272,621 1,068,308 3,305,353 3,330, ,71.5 3,433,629 3,4.55,679 1,245,169 3,607,23.5 7,414,602 3,679,397 2,255, , ,909 3,796, , B, c 1) B B, 15 B B, E, I3, B (not specified) F a, T. ferrooxidans; B, 7'. thiooxidans; C, T. concretivorus; I), denitrifying microorganisms including T. denitrificans; E, T. thioparua; F, Thiohacillus sp.

4 1856 BIOTECHNOLOGY ND BIOENGINEERING VOL. XVII (1975) the scientific literature. Furthermore, the disclosures in the patents are not always sufficiently comprehensive and unequivocal to enable an expert to reproduce the tests without recourse to further research work. In some patents the bacteria are described and classified loosely as thiobacilli using culture collection strains as reference. Only a few cultures described in the patents have been deposited in recognized culture collection centers such as the merican Type Culture Collection (TCC). Examples of such patent cultures include T. ferrooxidans TCC and TCC Some patent issues propose that useful cultures may be developed from listed culture collection strains such as T. ferrooxidans TCC and TC However, there is no evidence to show that the leaching on an industrial scale has been carried out by pure culture(s) of thiobacilli as claimed and assumed in some patent issues. Indeed, it is very unlikely that only one type of Thiobacillus would be active in the leaching of ores. It is not unusual to find a number of sulfur oxidizing bacteria and various heterotrophic microorganisms associated with ores in situ as well as in leaching operations. Given nutrients and appropriate growth conditions by adjusting the ph and aeration, then natural microbial popuations indigenous in the ore material may develop, whereas laboratory studies using pure cultures and possibly presterilized ore samples eliminate factors including mixed populations which occur in large-scale experiments and industrial operations. Moreover, little is known about microbial interactions such as mutualism and antagonism, which may be established in these operations. In general, there is no evidence to show that the strains described in the patents have any unique properties not previously known from the scientific literature. novel concept is to supply energy for the growth of bacteria by the oxidation of vanadium and uranium but the efficiency of these procedures has not been assessed. One patent claims the production of ammonia by denitrifying bacteria such as T. denitrificans, Micrococcus denitrificans, and Pseudomonas denitrificans, which contradicts the well-established fact that the main products of the dissimilatory nitrate and nitrite reduction are gases, e.g., nitric oxide, nitrous oxide, and nitrogen gas. Since the descriptions of the patent experiments, which are required by legislation, are based on the action of thiobacilli in pure cultures under laboratory conditions, the deposition of the patent strains is somewhat meaningless except for a few special instances since these strains may not be entirely responsible for leaching on an industrial scale. It is likely that several physiologically and ecologically different types of microorganisms thrive in leaching operations exhibiting a varying degree of adaptation to the prevailing conditions. This mixed population situation may be compared with a biological sewage purification process which is carried out by microorganisms of many types. Thus apart from the technical designs and constructions, which are currently covered by a number of patents, it is difficult to establish patent rights over these varied microbial populations. Like waste materials, most mineral ores are very heterogeneous in chemical composition and each is a unique substrate for microbial activity. It has been accepted that T. ferrooxidans be patented specifically for the production of ferric sulfate from pyrite and ferrous-iron since no other thiobacillus is known to mediate this reaction. (The two species of iron oxidizing bacteria previously classified as Ferrobacilli are now regarded as subspecies of T. ferrooxidans.) critical study is needed to establish whether unique differences can be

5 COMMUNICTIONS TO THE EDITOK 1857 demonstrated for the various strains of T. jerrooxidans. varying degree of adaptation may be envisaged based on variable concentrations of Fez+, Fe3+, and H+ as reported in published studies. It can be disputed, however, whether patent rights should be claimed for these adapted strains of 7'. ferrooxidans. CONCLUDING REMRKS The reactions ascribed in the patents to thiobacilli are common in natural environments and do not represent features produced by systematic selection and development. It is doubtful whether patent rights should be extended to these bacteria and their metabolic reactions. Perhaps thiobacilli may be regarded as components essential but not novel to the industrial process, in which the technical layout and construction are well specified and thus covered by patent rights. These organisms may therefore be used without infringing of any patent rights already issued, in processes which involve technical constructions that are different from the patented ones though employing similar microbiological principles. This account of the patents relating to thiobacilli suggests that this is a generally accepted guideline since all the patents assume the oxidation of ferrous-iron and inorganic sulfur compounds (metal sulfides) by these microorganisms. These views expressed on patents involving thiobacilli also relate to other patented microbiological processes which do not utilize presterile sealed fermentors and aseptic conditions with pure cultures of microbes. We conclude that more expertise and a closer scrutiny are required for executing improved standards for patents involving microbial processes and in justifying claims of patent practice and applications. The helpful and critical comments of Professors H. G. Gyllenberg and B. J. Ralph are gratefully acknowledged. This review was prepared during tenure of a Postdoctoral Research Fellowship from the ustralian Research Grants Committee (O.H.T.) and under Research Contract No. 1470/Rl/RB with the International tomic Energy gency. References 1. C. T. Taylor and 2.. Silberston, The Economic Impact of the Patent System..1 Study oj the British Experience, Cambridge University Press, London, J. W. Whittenburg, dvan. ppl. Microbiol., 13, 383 (1970). 3. H. G. Gyllenberg, Postepy Hig. Med. Dosw., 26, 423 (1972). 4. J. W. Baxter, World Patent Law and Practice, Sweet and Maxwell, London, C. W. Hesseltine and W. C. Haynes, Prog. Ind. Microbiol., 12, 1 (1973). 6. L. G. Silvestri and D. Gottlieb, Global Impacts ppl. Microbiol., 1, 109 (1964). Ilept. of gricultural Biochemistry Waite gricultural Research Institute The University of delaide Glen Osmond, South ustralia 5064 ccepted for Publication September 7, H. TUOVINEN I). J. D. NICHOLS