Recent processes in the biotechnology industry result in many byproducts that have potential values as soil amendment. Laboratory experiments were conducted to evaluate organic C mineralization of various biotechnology by‐products and their effects on glycosidases in soils. A soil sample was mixed with biotechnology by‐product material to approximate a field application of 9 g organic C kg−1 soil (0.9% or 50 Mg C ha−1), and incubated under aerobic conditions at room temperature (20 ± 2°C) for 30 d. The CO2 evolved was trapped in standard KOH solution by continuously passing CO2‐free air over the soil. Results showed that, in general, the amount of CO2‐C initially released increased rapidly, but differed among the biotechnology by‐product materials. Expressed as percentages of total organic C added, the amounts of CO2‐C evolved ranged from 0.5% with DEE in Weller soil (fine, montmorillonitic, mesic Aquic Hapludalfs) to 73.6% with FSL in Grundy soil (fine, montmorillonitic, mesic Aquic Argiudolls). Most of the CO2 evolution data conformed to a first‐order kinetic equation. The potentially mineralizable organic C values (Co) of the biotechnology by‐product‐treated soils ranged from 1.2 to 33.4 g C kg−1 soil. The half‐lives of the C remaining in soils ranged from 14 to 239 d. The rate constants of the first and second phases of decomposition (k1, and k2) were significantly correlated (r > 0.90***) with the percentages of CO2‐C evolved in 30 d. The k1 values fitted an equation similar to the Michaelis‐Menten kinetic equation with respect to total sugars, and the k2 values were significantly correlated with the high molecular‐weight organic C fractions (organic C ‐ total sugars, r = 0.42**) in the biotechnology by‐products. The biotechnology by‐products contained considerable amounts of cellulase, α‐ and β‐glucosidase, and α‐ and β‐galactosidase activities, contributing to decomposition of organic C in the biotechnology by‐products in soils. Several biotechnology by‐products are useful as soil amendments.
No takes yet. Share an insight, caveat, or question.
Martı́nez et al. (1997) studied this question.