NOVELTY - A primary hydrocarbon substrate (1) is formed into fluidized cellulose pulp slurry and introduced into a mesophilic bacterial bioreactor (7) to produce ethanol, volatile fatty acids, and hydrogen gas. Hydrogen gas is collected. The slurry overflow is introduced into a thermophilic bacterial bioreactor (15) within which volatile fatty acids and hydrogen are produced. The overflow is collected and separated into solid and liquid components (14,13). The solid component is introduced into mesophilic bacterial reactor, and liquid component is distilled.    USE - Simultaneous conversion of primary hydrocarbon substrate e.g. waste plant material, preferably sugarcane waste into biohydrogen, acetone, butanol and ethanol biosolvents, methane, and bioplastic or bioplastic storage product (all claimed).    ADVANTAGE - The method uses various particulate bacterial structures having excellent settling properties. The nitrogen and phosphorus content of the nutrient feed streams are reduced so as to promote the conversion of carbon substrates into bioplastic storage products.    DETAILED DESCRIPTION - A primary hydrocarbon substrate is treated to produce a fluidized cellulose pulp slurry. The slurry is introduced into a mesophilic bacterial bioreactor which, as a result of biological action of facultative anaerobic bacteria, is anaerobic and within which mesophilic bacteria, convert at least some low-molecular-weight or non-polymeric carbohydrates to ethanol, volatile fatty acids, and hydrogen gas and also at least partially digest cellulosic and hemicellulosic molecules in the slurry. Hydrogen gas is collected, and slurry overflow from the bioreactor is collected and treated to inactivate mesophilic bacteria in the slurry. The collected slurry is introduced into a thermophilic bacterial bioreactor within which volatile fatty acids and hydrogen are produced from digestion of slurry. Hydrogen is collected, and overflow from the bioreactor is collected and separated into solid and liquid components. The solid component is introduced into the slurry overflow from mesophilic bacterial reactor to recycle it through the thermophilic bacterial reactor. The liquid component is distilled to produce ethanol and distillate containing volatile fatty acid. Ethanol is collected, and fraction (I) of distillate is introduced into the mesophilic bacterial bioreactor with the fluidized slurry for recycling. Fraction (II) of distillate is introduced into a thermophilic methanogenic bioreactor (20) for conversion into methane (23). Fraction (III) of distillate is introduced into a bioplastic synthesizing bioreactor for conversion into bioplastic or bioplastic storage products (22), which are then collected. An INDEPENDENT CLAIM is included for bioreactor.    DESCRIPTION OF DRAWING(S) - The drawing shows a flow diagram of the conversion process of primary hydrocarbon into hydrogen, acetone, butanol, ethanol, bioplastics and methane.    Primary hydrocarbon substrate (1)    Mesophilic bacterial bioreactor (7)    Liquid component (13)    Solid component (14)    Thermophilic bacterial bioreactor (15)    Thermophilic methanogenic bioreactor (20)    Bioplastic storage product (22)    Methane (23)