Total organic carbon (TOC) of the vermicompost was estimated using the standard dichromate oxidation method of Nelson and Sommers (1982). Total Kjeldahl nitrogen (TKN) was estimated after digesting the sample with concentrated H2SO4 (1:20, w/v) followed by distillation (Bremner and Mulvaney, 1982). Total phosphorus (TP) and total potassium (TK) were analyzed from the wet digest [tri-acid (HNO3-H2SO4-HClO4) mixture was used for digestion] of vermicompost (Jackson, 1973). Total phosphorus (TP) was estimated by the colorimetric method using ammonium molybdate in hydrochloric acid and total potassium (TK) was determined by flame photometer (Bansal and Kapoor, 2000).

1.2 Microbial analysis

Microbial biomass was determined by the chloroform fumigation-extraction (FE) method (Vance et al., 1987). For fumigation, organic substrates were incubated with ethanol-free chloroform in desiccators. The TOC analyzer was used to determine total organic C (Corg) and total N in 0.5 M K2SO4 extracts of non-fumigated and fumigated soils. The microbial biomass carbon (MBC) was calculated as MBC = (Corg in fumigated soil — Corg in non — fumigated soil)/kc; where, kc = 0.33, the factor used to convert the extracted organic C to MBC (Sparling and West, 1988).

An analysis for ergosterol estimation was performed with 50 mg of lyophilized organic waste or vermicompost sample. Ergosterol was extracted from leaf litter by 30 min refluxing in alcoholic base (Gesser et al., 1991) and purified by solid-phase extraction. Final purification and quantification of ergosterol was achieved by high-performance liquid chromatography (HPLC). The system was run with HPLC grade methanol at a flow rate of 1.5 ml min-1. Ergosterol eluted after 7:11 min and detected at 282 nm; peak identity was checked on the basis of retention times of commercial ergosterol (98% purity).

The FAME analysis was performed using the modified procedure of Schutter and Dick (2000). Before analysis, fresh samples were lyophilized and three grams of lyophilized sample was treated with 10 mL of 0.2 M KOH in methanol and incubated at 37°C for 1 hr. After incubation, the pH of the system was adjusted to 7.0 with 1.0 M acetic acid, 10 mL of n-hexane was mixed and then it was vortexed. After centrifugation at 1600 rpm for 20 min., 5 mL of n-hexane layer was evaporated by N2 gas. The residue was dissolved in 170 pL of 1:1 mixture of n-hexane and methyl t-buthyl ether with 30 pL of 0.01M methyl nonadecanoate (C19:0) as internal standard for FAME and analyzed with a Hewlett-Packard 5890 Series II (Palo Alto, CA) equipped with an HP Ultra 2 capillary column (5% diphenyl — 95% dimethylpolysiloxane, 25 m by 0.2m) and a flame ionization detector. For FAME analysis, the oven temperature was raised from 170oC to 270oC at 5oC min-1 and kept at 2700C for 2 minutes.

Amino sugars in biomass suspensions, chloroform-fumigation-extraction (CFE) extracts and in incubated organic wastes were determined following standard method of Zhang and Amelung (1996). Sample aliquots corresponding to a about 50 mg microbial biomass, with 100 pg myo-inositol added as internal standard, were hydrolyzed with 10 ml of 6M HCl at 105 °C for 8 h. The CFE extracts were freeze-dried prior to hydrolysis. The released amino sugars were separated from impurities by neutralization with 0.4M KOH. Prior to derivatization, 100pg of methylglucamine was added as recovery standard. Derivatization was carried out according to (Guerrant and Moss, 1984). In brief, aldononitrile derivatives of the amino sugars were prepared by heating the samples in 0.3 ml of a derivatization reagent (32 mg hydroxylamine hydrochloride ml-1 and 40 mg 4-(dimethylamino) pyridine ml-1 in pyridine-methanol 4/1) at 75 °C for 30 min. After acetylation with 1 ml of acetic anhydride at 75-80 °C for 20 min, dichloromethane was added, and excess derivatization reagents were removed by washing with 1 ml of 1 M HCl and 1 ml of water two times each. The remaining organic phase was dried under an air stream at 45 °C and dissolved in 0.3 ml ethyl acetate — hexane (1/1). The amino sugar derivatives were separated on a HP 6890 GC equipped with a HP-5 fused silica column (30 m*0.25 mm ID with 0.33 ^m film thickness) and a flame ionization detector. Amino sugars were quantified using inositol as the internal standard and methylglucamine as recovery standard.