Variazioni di Metaboliti Nel Seme di Ricino in Fase di Maturazione

Abstract

Changes of glycolytic substrates level during ripening of the castor bean seed. — The changes of the concentration of carbohydrates and of the main glycolytic substrates in the castor bean seed during the ripening phase were investigated. The following results were obtained:

The level of unphosphorylated sugars and of acid hydrolysable polysaccharides remains almost unchanged, with a tendency to a rise during the ripening phase. The slight increase of these compounds, together with the transition of the R. Q. from high to low values, might be interpreted as an indication of a shift of the seed from the a metabolism of fat synthesis to one of conversion of lipids into sugars, such as is observed in the germinating castor bean seeds.

Hexose monophosphate level sharply decreases during the last period of maturation. However, the level of these substrates does not fall so low as to suggest a severe limitation for the pentose-P pathway activity.

Fructose diphosphate, DOAP, GAP, 3 PGA, 2 PGA, PEP and pyruvate levels consistently increase during the ripening process. This indicates that the drop of oxygen uptake observed in this phase cannot be due to a lack of glycolytic substrates. On the other hand, the ratios between some substrates are shifted, during ripening, from values close to the theoretical equilibrium constants to quite different values. This finding, when correlated with the one of the strong decrease of the glycolytic flow, strongly suggests a severe inactivation of the glycolyting enzymes during ripening.

The increase of pyruvate in tissues showing a decreasing respiratory activity indicates a fall of the oxidative capacity of mitochondria. This might be due to a lack of ADP, or other high energy bond acceptor, following a block of synthetic processes. However, no decrease of ADP level, and an increase of the ADP/ATP ratio during ripening is observed, Among the alternative hypothesis: a) lack or excess of oxalacetate; b) increase of concentration of some Krebs cycle inhibitor; c) inactivation of mitochondrial enzymes, the latter is thought most probable, in view of the finding of a sharp decrease of some other enzyme activities during ripening, of the above mentioned interpretation of the shift of the ratios between glycolytic substrates, and of the very low level of mitochondrial activity in preparation from the mature castor bean seed. These results when correlated with those from parallel investigations on the biochemistry of castor bean seed maturation and germination suggest, as a working hypothesis, that the respiratory metabolic inactivation accompanyng seed repening is due to a general block of the metabolism of ribonucleic acid and thus protein synthesis.     

Effetto di Inibitori Della Sintesi Proteica Sull'aumento di Attività Enzimatiche e sul Risveglio del Metabolismo Nell'Endosperma di Semi di Ricino in Germinazione

Abstract

Effects of inhibitors of protein synthesis on the development of metabolic activity in the endosperm during the germination of castor bean seeds. — The effect of chloramphenicol, streptomycin and actinomycin-C on the increase of the activities of glyceroaldehyde-phosphate dehydrogenase, aldolase, glucose-6-phosphate dehydrogenase, fructose 1–6 diphosphate-1-phosphatase, phosphomonoesterase, in the endosperm of germinating castor bean seeds was investigated.

In all cases, the protein synthesis inhibitors depressed the activation of the enzymes tested: in particular, actinomycin (50 μg/ml) completely suppressed the increase of the activities.

The development of the rate of oxygen uptake and the conversion of fats to sugars was strongly affected by the inhibitors.

These data suggest that the increase of the activities of several enzymes in the germinating endosperm is dependent on enzyme synthesis rather than on the conversion from the inactive to the active form of the enzymes.     

Osservazioni Preliminari sui Sistemi Degradanti dell'RNA nei semi di Ricino

Abstract

Preliminary observations on the enzymatic degradation of RNA in castor bean seeds. — Cocucci, Maggio, Monroy and Marrè have shown the decrease of RNA content during ripening in castor bean seeds, and its increase during germination. Furthermore, these Authors have demonstrated that in the dry ripe seeds the ribosomes are undetectable, and that they increase rapidly during germination. Two peaks of ribosomes are easily detected upon ultracentrifugal analysis in germinating seeds (Cocucci and Sturani). These observations were the basis for our investigations of the enzymes of RNA metabolism in castor bean seeds. This paper deals with our preliminary observations on RNA degrading enzymes in these tissues. We have been able to measure RNase activity, phosphodiesterase, 3′-,5′- and 2′-nucleotidases in castor bean seeds at different stages of development. RNase activity (measured in crude extracts) changes little during the ripening process, its rate corresponding to 40–50 μMoles of nucleotides liberated from RNA per hour and per gram of fresh weight. In the dry seeds, RNase activity is 30–40 μMoles of nucleotides/h.g.f.w., and it increases to about 60–70 μMoles/h/g.f.w. after 72 hours of germination.

Phosphodiesterase activity is about 4–5 μMoles/h.g.f.w.

The following rates have been found in seeds almost completely ripe seeds for 3′-, 5′- and 2′-nucleotidase activities, respectively 45–50 μMoles/h.g.f.w.; 6–7 μMoles/h.g.f.w.; 8 μMoles/h.g.f.w.; ATP-ase activity was of about 80–100 μMoles of phosphate liberated /h.g.f.w. - The high activity of 3′-nucleotidase, of the same order of that of RNase, suggests that these two enzymes are responsible for degradation of RNA to nucleosides and inorganic phosphate. Further investigations are being carried on to define the biochemical properties of castor bean RN-ase.     

Fungicidal effect of ultraviolet-C radiations in prevention of mycoflora of castor bean seeds

The effect of ultra violet (UV-C) radiation on germination and fungal flora of castor bean seeds was estimated with different doses stored up to 80?days interval. Results revealed that 20 and 40?min radiated castor bean seeds showed complete reduction in most of the fungi while germination of castor bean seeds were enhanced when UV-C radiations applied for 20?min. Increasing the radiation doses and storage period has been shown decrement in Aspergillus species colonisation.     

Protein Synthesis During Rehydration, Germination and Seedling Growth of Naturally and Precociously Matured Soybean Seeds (Glycine max)

p. 86, line 6, should read: These patterns of soluble protein synthese are similar to thoseobserved after precocious maturation and subsequent rehydrationof castor bean (Kermode and Bewley, 1985a, b, 1986), and withinaxes of Phaseolus vulgaris L. seeds (Dasgupta and Bewley, 1982). instead of: These pattern of protein synthesis. Unlike castor bean thoseobserved after precocious maturation and subsequent rehydrationof castor bean (Kermode and Bewley, 1985a, b, 1986), and withinaxes of Phaseolus vulgaris L. seeds (Dasgupta and Bewley, 1982).     

Fenomeni di Inattivazione e di Riattivazione Enzimatica in Endospermi di semi di Ricino

Abstract

Inactivation and riactivation of enzymes in endosperms of castor bean seeds. — On the basis of previous results, the possibility has been investigated of the reversible interconversion of active and inactive form of enzymes in castor bean seeds, during their development.

The results described here indicate that:

1. the activity of some glycolytic enzymes increases greatly (81% and 400% increase of, respectively, Gl-6-P-dehydrogenase and aldolase) upon incubation of dry seeds for few hours at 4 °C.

2. The decrease of enzyme activity upon dehydration of seeds and the increase during the subsequent imbibition can be shown reproducibly.

3. This same observation is made for oxygen uptake.

These results are interpreted to indicate the reversible inactivation of enzymes caused by dehydration of seeds.     

Rapporti Tra Assunzione D'acqua,Metabolismo e Sintesi di Enzimi Nell'endosperma Di Semi Germinanti di Ricinus Communis

Abstract

Water uptake, activation of metabolism and enzyme synthesis in germinating castor bean seeds. — During the first days of germination water uptake by the castor bean seed endosperm is accompanied by a rapid rise of respiratory activity and of the « in vitro » detectable activity of a number of enzymes. The finding that the increase of enzyme activity is strongly inibited by protein synthesis inhibitors suggests an « ex novo » synthesis of enzymes in the endosperm of the germinating seed. The present investigation on the relationship between water uptake, metabolic activity and enzyme activity level lead to the following conclusions:

I - The increase of enzyme activity is strictly dependent on the availability of water, and on the rate of water uptake. When water uptake is depressed by incubation of the seed in high osmolarity media, enzyme activation is also severely depressed.

This is also observed when the seeds are germinating in contact with an amount of water consistently lower then the one they would taken up, in a given time (24 h), under conditions of unlimeted water availability.

II - The temperature coefficient of water uptake is close to 1.5 during the first 24 h, higher than 2 in the following 3 days. Low temperature almost completely inhibits the increase of enzyme activities in the endosperm.

III - Anaerobiosis inhibits the rate of water uptake by about 50%, in the first 24 h, and almost completely, in the following 3 days. Also the rise of enzyme activities is severely inhibited by lack of oxygen. The effect of protein synthesis inhibitors on water uptake is somewhat smaller, and the one on enzyme activity is somewhat larger than that of anaerobiosis.

These results are interpreted as indicating that during the early period of germination water uptake becomes more and more dependent on the metabolic activities of the endosperm cells, in as much the latter lead to the appearance of osmotically active substances and, possibly, to changes of the cell wall properties.

On the other hand, the level of hydration of the cytoplasm represents a limiting factor for the development of the mechanism involved in enzyme synthesis and metabolic activation.     

Inattivazione dei Mitocondri Negli Endospermi di Ricino Durante la Maturazione

Abstract

inactivation of mitochondria in the castor bean seed endosperm during ripening. — The present research deals with the behaviour of mitochondria from the endosperm of castor bean seeds, during the last phases of seed maturation. The activities of citochrome oxidase, of malate dehydrogenase, of the succinate-citochrome c reductase system, and the phosphorylating activity, were chosen as tests of the state of mitochondria.

The results obtained show an increase of the first two activities up to the moment when some ovular tissues are still present, and, successively, a more or less rapid inactivation of the three enzymes investigated, which fall to extremely low values in the dry seed. Also the phosphorylating capacity, high during the first phases, drops quickly as the seed approches to dormancy.

A certain amount of citochrome oxidase is revealed in the supernatant from 20000xg centrifugation made to prepare the mitochondrial fraction; its activity gradually increases as the seed advances to ripeness. A further fractionation of the activity not sedimenting at 20000xg reveals that approximately one half of it sediments when centrifugated for 1 hour at 50000xg, while the other half remains in the supernatant. The particles sedimenting between 20000 and 50000xg show very little, if any, phosphorylating capacity (with succinate).

It is suggested that the gradual inactivation of mitochondrial efficiency during the ripening phase is due to a degradation of mithochondrial structures.     

Aspetti Enzimatici Della Maturazione e Germinazione dei Semi di Ricino

Abstract

Enzyme levels during ripening and germination of castor bean seeds. — During the development of the endosperm of castor bean seeds two distinct phases can be recognized: pre-maturation and germination. The former is characterized, metabolically, by the rapid conversion of carbohydrates into lipids, and storage proteins. The latter is characterized by the reconversion of these storage materials into sugars. Both these processes are dependent upon the activity of the glycolytic pathway; for this reason the behaviour of some enzymes of this pathway and, in general, of the carbohydrate metabolism have been studied during the two phases. The changes (during the evolution of the seeds) of the following enzymes have been studied:

Gl-6-P-dehydrogenase, 6-P-gluconate dehydrogenase, P-glucomutase, Hexokinase Hexoseisomerase, Aldolase, alcaline and acid Phosphatase, Pyrophosphatase and ATP-ase.

All these activities have been measured in the 20.000 × g supernatant fraction of cell homogenates.

The results show that all the enzymes activities measured increase rapidly during the period of accumulation of storage materials. In the following period all of these activities decrease until the stage of ripeness of the seed. During the first few days of germination the activities increase again rapidly. A particular behaviour is the one of Fr-1-6-P-phosphatase (the enzyme cleaving the phosphate bond in C ¹ position). This enzyme reaches during germination a level much higher than the maximal observed during the ripening process. This might be an important fact correlated with the inversion of the glycolytic reactions during germination.     

Osservazioni Sull'effetto Inibente di Elevate Pressioni Osmotiche su Diversi Tipi di Crescita

Abstract

On the inhibition of seeds germination and of growth by cell enlargement by the osmotic pressure of the medium. — The mechanism of inhibition by osmotic pressure (O.P.) of the medium on growth and respiration of germinating wheat, castor bean and lettuce sèeds and of etiolated pea internode segments was investigated.

The following results were obtained:

1 - External osmotic pressure (up to 0.3 M) of various substances such as mannitol, urea, glucose, NaCl, was shown to inhibit the germination and growth of lettuce, wheat and castor bean seeds.

2 - a) A remarkable decrease of the development of respiration during the first 48 h of germination was demonstrated in embryos of wheat seeds germinated and maintained in mannitol solutions at concentration from 0,2 to 0,3 M.

b) A slight but reproducible inhibition of óxygen uptake by O.P. was also observed in embryos isolated from wheat seeds germinated in water for 24 and 34 h and transported respectively in water or into 0,2 M mannitol solutions.

This is interpreted as indicating that high external O.P. inhibits both the respiratory metabolism and the development with time of enzyme systems supporting respiration.

3 - Mannitol solutions (0,2–0,3 M) inhibited completely growth by cell enlargement in pea internode sections, while they did not at all affect oxygen uptake and protein synthesis ( ¹⁴ C - leucine incorporation). The stimulatory effect of auxin on pea elongation was almost completely suppressed by mannitol, whereas the hormone stimulation of respiration remained unchanged.

These data are interpreted as indicating that in tissues, presenting an advanced differentiation, high external O.P. inhibits growth by a direct physico-chemical mechanism; while the inhibitory effect in embrional tissues seems to comprehend, besides this direct effect, a complicated metabolic component, apparently influencing protein synthesis.     

Effetto della Presenza di Zuccheri Sull'attivita Esochinasica in Cotiledoni Germinanti di Ricino

Abstract

The effects of sugars on the development of hexokinase and fructokinase activities in isolated cotyledons from germinating castor bean seeds. — The possibility of an inductive effect of hexose concentration on the rate of synthesis of enzymes involved in the phosphorylation of sugars has been investigated. Cotyledons were removed from castor bean seeds germinated 48 h at 27 °C in the dark, and incubated 12 h in water or in 0,05–0,1 M glucose or fructose. The activities of hexokinase and of fructokinase (determined spectrophotometrically in the soluble fraction from cell free extracts) was found to increase, upon incubation, at a rate more than 100% higher for the cotyledons incubated in the presence of sugars than for those in water. The results suggest some specificity of the effect of fructose on fructokinase and of glucose on hexokinase. « Insoluble » hexokinase was not affected by the sugars. Protein synthesis inhibitors such as actinomycin D and puromycin inhibited any increase of kinase activities in the isolated cotyledons.     

Attività Respiratoria Livelli Enzimatici e Tenore in Acqua Durante la Maturazione del Seme di Ricino

Abstract

Respiratory activity, enzyme levels and water contents in the ripening castor beans seed endosperm. — In the endosperm of the developing castor bean seed oxygen uptake, water contents and the « in vitro » measurable activity of various enzymes parallely drop during the terminal strages of ripening. The present investigations shows that also the capacity of water uptake decreases (and that of water loss increases) during ripening.

When developing seeds at a stage close to ripeness are removed from the fruits and incubated under a condition of easy water availability, both respiration and enzyme activities rapidly rise; while this is not observed for seeds removed from the fruit at an earlier stage of development.

These results are interpreted as indicating that the dehydration of the seed during ripening is both a consequence and a cause of the inactivation of enzyme systems.     

Lipases in the storage tissues of peanut and other oil seeds during germination

The castor-bean endosperm-the best-studied material of reserve lipid hydrolysis in seed germination-was previously shown to have an acid lipase and an alkaline lipase having reciprocal patterns of development during germination. We studied oil seeds from 7 species, namely castor bean (Ricinus communis L.), peanut (Arachis hypogaea L.), sunflower (Helianthus annus L.), cucumber (Cucumis sativus L.), cotton (Gossypisum hirsutum L.), corn (Zea mays. L.) and tomato (Lycopersicon esculentum Mill.). The storage tissues of all these oil seeds except castor bean contained only alkaline lipase activity which increased drastically during germination. The pattern of acid and alkaline lipases in castor bean does not seem to be common in other oil seeds. The alkaline lipase of peanut cotyledons was chosen for further study. On sucrose gradient centrifugation of cotyledon homogenate from 3-d-old seedlings, about 60% of the activity of the enzyme was found to be associated with the glyoxysomes, 15% with the mitochondria, and 25% with a membrane fraction at a density of 1.12 g cm^-3. The glyoxysomal lipase was associated with the organelle membrane, and hydrolyzed only monoglyceride whereas the mitochondrial and membrane-fraction enzymes degraded mono-, di- and triglycerides equally well. Thus, although the lipase in the glyoxysomes had the highest activity, it had to cooperate with lipases in other cellular compartments for the complete hydrolysis of reserve triglycerides.     

Characterization of asparaginyl endopeptidase activity in endosperm of developing and germinating castor oil seeds

A spectrophotometric assay was devised to characterize the asparaginyl (Asn) endopeptidase activity from the endosperm of castor oil seeds. (Ricinus communis L. var. Baker 296). The assay measures the release of p-nitroaniline from the hydrolysis of benzoyl-l-Asn-p-nitroanilide. Assay sensitivity was improved through diazotization of the reaction product with N(]-napthy])-ethylenediamine dihydrochloride: diazotized p-nitroaniline was determined spectrophotometrically at 548 nm (?₅₄₈= 1.64 × 10^?1M^?1 cm^?2). By using this assay. Asn endopeptidase activity was detected in endosperm extracts of developing, mature and germinating castor seeds. Comparison of the Asn endopeptidase activities of developing and germinating castor endosperms revealed that they: 1) have identical pH-activity profiles with optimal activity occuring at pH 5.4: 2) are heat-labile proteins displaying comparable thermal stability profiles, and 3) are activated and inhibited by dithiothreitol and thiol modifying reagents, respectively. Thus, the Asn endopeptidases of developing and germinating castor seeds are very similar, if not identical, cysteine proteases. The most significant increase in the activity of endosperm Asn endopeptidase occurs during the full coryledon to maturation stage of seed development, this period coincides with the most active phase of reserve protein accumulation by ripening castor oil seeds. Asn endopeptidase activity of fully mature (dry) castor seeds was about 2-fold lower than that of muturation stage ripening castor oil seed. Asn endopeptidase activity showed a slight reduction over the inicial 2-day period following seed imbibition, and then rapidly decreased over the next several days of germination. The results are compatible with the proposal that Asn endopeptidase functions both to process storage preproteins following their import into protein bodies of developing seeds, as well as to participate in the mobilization of storage proteins during the early phase of seed germination.     

Developmental changes in endosperm of germinating castor bean independent of embryonic axis

Dry castor bean (Ricinus communis) seeds were cut transversely into halves and the half without the embryonic axis was placed in moist vermiculite at 30 C for 5 days. The development of the endosperm in the half-bean was found to be qualitatively similar to that in the whole seedling in the appearance of various enzymes of gluconeogenesis, the accumulation of glucose and sucrose as the end products of fat utilization, and the development of subcellular structure. It is concluded that during germination of castor bean, the embryonic axis does not directly control the developmental changes in the endosperm.     

Patterns of mitochondrial development in reserve tissues of germinated seeds: A survey

Patterns of mitochondrial development in reserve tissues of several species of seeds were examined during 3 to 4 days after the start of imbibition. In starch-storing seeds (cowpea, kidney bean, Egyptian kidney bean, mung bean, black gram and soybean), mitochondrial activities (state 3 respiration rate, respiratory control ratio) increased during the first 1 to 2 days after imbibition and leveled off thereafter. The initial increase in the activities was little affected by cycloheximide and chloramphenicol. Activities of mitochondrial enzymes (succinate dehydrogenase, EC 1.3.99.1; NAD⁺-malate dehydrogenase, EC 1.1.1.37; cytochrome oxidase, EC 1.9.3.1) did not change much during the experimental period. This suggests that mitochondrial development in starch-storing seeds is primarily due to improvement of pre-existing mitochondria. On the other hand, in the lipid-storing seeds examined (pumpkin, cucumber, okra and castor bean), the rate of mitochondrial respiration and activities of mitochondrial enzymes continued to increase markedly during the experimental period. These increases were strongly inhibited by cycloheximide and chloramphenicol. This indicates that active de novo synthesis of mitochondrial proteins is primarily responsible for the development of organelle activities. The possibility was suggested that the patterns of mitochondrial development in reserve tissues of imbibed seeds might be determined by the kinds of reserve substances.     

A cysteine endopeptidase with a C-terminal KDEL motif isolated from castor bean endosperm is a marker enzyme for the ricinosome, a putative lytic compartment

A papain-type cysteine endopeptidase with a molecular mass of 35 kDa for the mature enzyme, was purified from germinating castor bean (Ricinus communis L.) endosperm by virtue of its capacity to process the glyoxysomal malate dehydrogenase precursor protein to the mature subunit in vitro (C. Gietl et al., 1997, Plant Physiol 113: 863–871). The cDNA clones from endosperm of germinating seedlings and from developing seeds were isolated and sequence analysis revealed that a very similar or identical peptidase is synthesised in both tissues. Sequencing established a presequence for co-translational targeting into the endoplasmic reticulum, an N-terminal propeptide and a C-terminal KDEL motif for the castor bean cysteine endopeptidase precursor. The 45-kDa pro-enzyme stably present in isolated organelles was enzymatically active. Immunocytochemistry with antibodies raised against the purified cysteine endopeptidase revealed highly specific labelling of ricinosomes, organelles which co-purify with glyoxysomes from germinating Ricinus endosperm. The cysteine endopeptidase from castor bean endosperm, which represents a senescing tissue, is homologous to cysteine endopeptidases from other senescing tissues such as the cotyledons of germinating mung bean (Vigna mungo) and vetch (Vicia sativa), the seed pods of maturing French bean (Phaseolus vulgaris) and the flowers of daylily (Hemerocallis sp.). Received: 20 December 1997 / Accepted: 18 March 1998     

Host plant effects on the functional response of Stethorus gilvifrons to strawberry spider mites

The functional response of adult females of the coccinellid beetle Stethorus gilvifrons Mulsant to juveniles of strawberry spider mite, Tetranychus turkestani Ugarov & Nikolski was determined on cowpea, castor bean and cucumber leaves in the laboratory at 25°C and a 14 h L: 10 h D photoperiod. Beetles were isolated singly for 24 h in 9-cm Petri dishes with either 2, 4, 8, 16, 32, 64, or 128 nymphal stages of T. turkestani. Results showed a typical type II response on all plants tested, with up to 110.7, 100.8, and 53.0 prey attacked when 128 nymphal stages were provided on cowpea, castor bean, and cucumber leaves, respectively. Based on the Rogers random attack equation, the highest estimated attack rate and the lowest handling time were obtained on cowpea. It was therefore concluded that the host plant species can affect the predation rate and functional response components of S. gilvifrons, a specific and effective predator of spider mites.     

Females of the weevil Zabrotes subfasciatus manipulate the size and number of eggs according to the host seed availability

Abstract. In some insects, the finding of oviposition substrate triggers the uptake into oocytes of yolk proteins that are stored in the fat body during post‐embryonic development. The main host of the bean weevil Zabrotes subfasciatus (Coleoptera; Chrysomelidae; Bruchinae; Amblycerini), in which larval resources are the sole source for future egg maturation, is Phaseolus vulgaris. Despite not feeding as adults, females of this species are able to lay eggs after encountering host seeds but it is not known how females react to changes in the availability of bean seeds. In the present study, the behaviour of Z. subfasciatus facing two very different environments for oviposition is investigated, as well as how this influences offspring fitness. The results obtained show that females of Z. subfasciatus react to variations in the availability of seeds belonging to the same host species by adjusting egg size and number. Females on low bean seed density lay larger and fewer eggs than those on high bean seed density, demonstrating a trade‐off between these reproductive traits. Moreover, females can adjust egg size to changing levels of host availability during the first 4 days of their oviposition period. Although no difference in offspring weight is found, those from small eggs (low competition environment) result in larger adults. No response to selection on these traits after rearing beetles on the same host for 40 generations is observed. This unresponsiveness may indicate that beetle populations behave according to their reaction norm that already allows rapid adaptation to a varying amount of host‐seed availability and better exploitation of the environments of this widespread stored‐seed pest.     

Use of a low-cost methodology for biodetoxification of castor bean waste and lipase production

The castor bean (Ricinus communis) represents a potential candidate for biodiesel production. The Petrobras Research Center is developing a biodiesel production process from castor bean seeds, in which an unwanted byproduct named castor bean waste is produced. This extremely alkaline waste is toxic and allergenic and, as such, poses a significant environmental problem. Solid-state fermentation (SSF) of castor bean waste was carried out to achieve ricin detoxification, reduce allergenic potential and stimulate lipase production. The fungus, Penicillium simplicissimum, an excellent lipase producer, was able to grow and produce lipase enzyme. After an optimization process, the maximum lipase activity achieved was 44.8 U/g. Moreover, the fungus P. simplicissimum was able to reduce the ricin content to non-detectable levels in addition to diminishing castor bean waste allergenic potential by approximately 16%. In this way, SSF of castor bean waste by P. simplicissimum may increase the utility of the waste by promoting enzyme production and eliminating the principal toxic element, ricin.