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16 Bioreactors for the Production of Industrial Chemicals and Bioenergy Recovery from Waste

bioreactors confirmed higher manufacturing of citric acid compared to flask

cultures. A higher citric acid yield in packed-bed column bioreactors using cassava

bagasse was reported. Enhanced ventilation and heat and mass transfer effects were

considered to be the cause for this [32]. Diverse mechanisms of heat elimination

(conductive, convective, and evaporative) from packed-bed bioreactors in SSF for

citric acid manufacturing with a lifeless carrier were evaluated. Results confirmed

that the conductive heat transfer was the least efficient method (8.65%) compared

to convective (26.65%) and evaporative (64.7%) heat transfer. Fungal as well as

bacterial strains have been utilized for lactic acid manufacturing in SSF. Strains

of Rhizopus and Lactobacillus were used. Diverse crops such as cassava and sweet

sorghum and crop residues such as sugarcane bagasse, sugarcane press mud, and

carrot-processing waste were utilized as substrates in these practices.

16.8.4

Biopesticides

Problems created by insects and pests to agriculture industry can be effectively met

by biopesticides which are considered environment-friendly. Currently, the use of

entomo pathogenic and mycoparasitic fungi for biological control of insects and

pests has created growing awareness. Challenges have been taken to produce entomo

pathogenic fungi in SSF. In the SSF-based process, numerous agro-industrial sub-

strates were considered for generating spores from Beauveria bassiana which can

be used to prevent pests in banana, sugarcane, soybean, and coffee. The B. bassiana

was produced in SSF for use against European corn borer. The bio-insecticide was

produced in a 1600-l capacity industrial reactor. The bioproduct exhibited a field

effectiveness of 80%. The Colletotrichum truncatum is a new fungal plant pathogen,

which showed assurance as a bioherbicide against the hard weed Sesbania exaltata.

The C. truncatum spores were formed in SSF which use solid support such as solid

perlite-corn meal-agar and vermiculite [32].

16.8.5

Aroma Compounds

Plants are the key sources of essential oils and flavors, but their exploitation depends

on the factors which are not easy to control, such as weather conditions and plant

diseases. An unusual route for flavor production is based on microbial biosynthesis

or bioconversion. An attempt to exploit microorganisms in SmF resulted in low

production, which troubled industrial use of these procedures. The SSF could be of

elevated probability for this intention from agro-industrial residues such as cassava

bagasse, sugarcane bagasse, coffee husk, coffee pulp, etc. Fungi from the genus

Ceratocystis synthesize a huge variety of fruit- or flower-like fragrance (peach,

pineapple, banana, citrus, and rose) based on the culture and its growth conditions.

Among the species, Ceratocystis fimbriata has an enormous possibility for ester

production. Although amaranth medium formed pineapple aroma, medium with

other substrates created strong fruity odor. Aroma recovery was growth-dependent

and greatest strength was identified within few hours previous to or following

the highest respiratory activity. Synthesis of strong pineapple fragrance was also