Hitachi, Ltd.

Agency of Industrial Science and Technology

Hitachi Plant Engineering Construction Co., Ltd.

Ryooichi Haga

Masahiko Ishida

Youji Odawara

Yoji Odawara

Masako Katsurayama

Sankichi Takahashi

Katsuya Ebara

This invention provides a process for easily recovering nearly white starch and protein having a high commercial value by depressing darkening of crushed slurry and juice in producing starch and protein of a subterranean stem. The above-mentioned process is characterized by adding at least one member selected from the group consisting of sodium thiosulfate, potassium thiosulfate, sodium hydrogen sulfite, sodium sulfite and potassium sulfite at the time of crushing the subterranean stem.

Process for recovering subterranean stem starch and protein

The bacterium producing thermostable .alpha.-amylases of this invention is an anaerobic bacterium belonging to Clostridium. The thermostable .alpha.-amylases of this invention is novel .alpha.-amylases which are excellent in thermostability and acid resistance and have a slight calcium requirement. Said .alpha.-amylases are obtained by culturing the aforesaid bacteria and collecting the .alpha.-amylases from the culture. When the aforesaid .alpha.-amylase is used, sugar production process can be greatly rationalized.

Thermostable .alpha.-amylase-producing, thermophilic anaerobic bacteria,

This invention relates to a process for liquefying starch. More particularly it relates to an appropriate process for liquefying starch by using a thermostable .alpha.-amylase which has an optimum working pH range in an acidic region and a low calcium requirement. This invention provides a process for liquefying starch by using a calcium-requiring, thermostable .alpha.-amylase which requires a calcium concentration of 10 .mu.m or below under a thermostable condition. In the process of the present invention, it is unnecessary to add a calcium salt in liquefying starch and the starch slurry can be reacted while remaining acidic without neutralization, so that the load at the desalting step of the product can be significantly relieved.

Process for liquefying starch

First, the organic waste slurry of sewage sludge and/or kitchen garbage is stored in a stable condition after effecting partially thereto a liquefaction treatment in advance by adding liquefying bacteria, and next this slurry is effectively digested anaerobically by way of a liquefaction/gasification-mixed step or a liquefaction/gasification separated step.

Anaerobic digestion process

Method for treatment of biochemical waste which comprises adding acid to the biochemical waste to adjust pH (power of hydrogen ion) thereof, heating the adjusted biochemical waste, adding alkali thereto to neutralize the waste, and treating with anaerobic digestion.

Method for treatment of biochemical waste

A process for the tertiary treatment of biochemical waste waters comprising the following 4 main steps; (1) adding milk of lime to waste water from the anaerobic digestion treatment process to render the waste water alkaline and recovering NH.sub.3 by reduced pressure distillation, (2) contacting recovered NH.sub.3 with a weakly acidic ion exchange resin to make NH.sub.3 adsorbed in the ion exchanger resin, (3) adding acid to the adsorbed ammonia to form an ammonia salt, and (4) blowing CO.sub.2 into the treated water from which NH.sub.3 has been removed, to thereby recover P, and subjecting the treated water from which N and P have been removed to the activated sludge treatment to remove BOD.

Process for tertiary treatment of waste waters from anaerobic digestion

In a system for treatment of biochemical waste such as activated sludges, the waste is subjected to anaerobic stabilization processes, which include two phases of an acid fermentation and a methane fermentation effected in separate reactors. The waste after the acid fermentation is then separated into a liquid effluent for the methane fermentation and a waste sludge. The waste sludge which may cause secondary environmental pollution is re-treated within the anaerobic stabilization processes without withdrawing from the system.

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Hitachi, Japan

Ryooichi Haga