PRESENTATION

Problem: the lethality of cassavaHypothesis :Treating cassava with radiation

can avoid that.Aim is to decompose proteins enzymes that

cause the decomposition of cyanoglycosides.

Project : pesticide manufacturing

Contents.

• Introduction• Chemical description of( hydrogen cyanide and its

derivatives).• Industrial & laboratory production of HCN.• Uses of HCN.• Physiological description of Hydrogen cyanide

intoxication.• Antidote of HCN intoxication.• Different ways of preparing cassava tubers and leaves

in order to avoid their toxicity.• My project

Introduction

Cassava tubers and leaves are edible

Cassava plant & HCN

• Cassava plant is among major plants that are mostly cultivated in some tropical regions and it becomes the frequent food for population of those regions , NIGERIA is the first country that cultivate cassava in the world . Its tubers and leaves are edible either by direct consumption or after the transformations .thereby to get different food like Eba,fufu,..

• The tubers are potentially made of carbohydrates as the main source of nutrient rather than protein,but also the there exist small proportion of Cyanide compounds ,that exit in two carbohydrates forms(cyanogenic glucosides):LINAMARIN &LAUTOSTRALIN.

Chemical description of HCN

This is chemical structures of HCNHCN is easily dissociate in water or basic medium

HCN(aq) + H2O(l) = CN-(aq) + H3O+(aq).The anion CN- is the strongest nucleophile in all

substitution organic reactions or complex formation, as it is so-electronic with CO(carbon monoxide)

Industrial & laboratory preparations.

Industry scale[Andrussow process]

I)2CH4(g)+2NH3(g)+3 O2(g)/Pt → 2HCN+6H2O

Laboratory scale

H++NaCN→HCN+Na+aq

Uses of HCN

It is used as precursor of NaCN and KCN that are used in gold and silver mining .

HCN allows chemists to have CYNOHYDRIN as the intermediate compound in formation of many

important organic compound.

Physiological effect of Cynides(partI)

When CN- get into body by inhaling HCH or CN- in solution,it spread quickly in human body after the intake,

As we said in the root of cassava plant there exist two forms of cyanogenic gycosides that are decomposed naturally byenzyme called LINAMARASE,to give HCN which very toxic to human

and animalOnly 40mg of pure cyanogenic gycoside can directly kill a cow,as the concentration of that compound vary from[…………]according to the types of cassava plant and theirs seasons in

which they were planted.The bitter cassavas have much HCN,sweeter have less HCN.

The cassava of dry seasons have much HCN that of rainy seasons

Physiological effect of cyanides(partII)

When CN-get into body ,especial in blood system,as said above CN- is the strongest nucleophile ,it replace other nucleophiles attached on copper ion that makes respiration enzyme reason

why it impair the respiration by inhibiting the CYTOCROME OXIDASE,which is the respiratory enzyme in elecrton chain

transport ( important step of cellular respiration in ATP production).

As result man or animal can get in coma(ataxia), or death due to lack of ATP and oxygen cellular intake

ANTIDOTE OF HCNHydroxocobalamin is used as an antidote in order to

react with it and form cynocobalamin which non harmful,but after few minutes of intake.

(cynokit brandname).

+ -

Radiation cassava treatment.

1)Pre-plantation methods(genetic transformation)

2)Pre-consumption method(protein decomposition)

Pre-plantation radiation step

As the genes producing enzymes in cassava plant cells are able to be modified into

other genes,It is possible to shift the bitter

type into sweet one ,using genetic transformation( radiating these genes) for the plantation to

be introduced or Transforming them in the best type that can not produce any

enzyme among those that cause the HCN formation from

cynoglycosides.

Pre-consumption radiating method

The harvested tubers ,and leaves may be treated by radiation so that the unused enzymes that

transform glucosides into HCN , can be the antidote by neutralizing CN- physiological effect.