Linear Alkylbenzenesulfonate (Las) Surfactants in a Simple Test to Detect Refractory Organic Carbon (Roc): Attribution of Recalcitrants to Impurities in Las

Abstract

The standard procedure to examine the biodegradability of a (group of) compound(s) in a trickling filter is a continuousflow system. In this test, nondegraded metabolites from a commercial linear alkylbenzenesulfonate (LAS) surfactant are detected (Kolbener, Baumann, Leisinger, and Cook; accompanying paper). This procedure has now been augmented by two phases in closed cycle to give a test for refractory organic carbon (ROC test). First, the concentration of nondegraded metabolites was increased by readdition of LAS to the solution being cycled through the filter. Second, the concentrated residues were further recycled till the net dissolved organic carbon (DOC) stabilised at a finite value and the net released CO, stabilised at about zero. The organic compounds remaining at this phase of the experiment were considered recalcitrant and could be examined by global (e.g., DOC) and specific (e.g., HPLC) assays. Four different commercial preparations of LAS were examined, as were the (4-su1fophenyl)undecane homologue (C, l-LAS), the (4-sulfophenyl)dodecane homologue (C ,,-LAS), and some related compounds. The four commercial LAS preparations contained different levels of impurities (2% to about 17%, according to the producers), which were largely dialkyltetralinesulfonates (DATS) and branched-chain alkylbenzenesulfonates (bABS). The refractory organic carbon (ROC) remaining after biodegradation varied from 3 to 14%. The results were a characteristic of the LAS under study and were independent of the source of the biomass used in the experiment. Residues were examined by HPLC, and 50 to 100 peaks were observed, which were usually characteristic of the LAS studied. No peak has been conclusively identified. We consider the recalcitrants to represent carboxylated DATS and carboxylated bABS.

Mineralization of Individual Congeners of Linear Alkylbenzenesulfonate by Defined Pairs of Heterotrophic Bacteria

“…1) is fully biodegradable (21,22), and degradative organisms were isolated in laboratories which did not have extensive analytical capabilities to explore their physiology in detail (13,16,33). Schulz et al (32) found that their isolate, D. acidovorans SPB1, has a very narrow substrate spectrum for SPCs, namely, RS-2-C4-SPC, which are degraded sequentially, the S enantiomer first.…”

Enantiomeric Degradation of 2-(4-Sulfophenyl)Butyrate via 4-Sulfocatechol inDelftia acidovoransSPB1

“…The eluate from the trickling filter was chromatographed (26), the fractions corresponding to the desired material were collected and subjected to solidphase extraction to remove the perchlorate in the mobile phase (28), and the neutralized material was used in growth medium.…”

“…Whereas the degradation of LAS is well established (16,26,27,35,39,43), the mechanisms of its degradation are not (4).…”

Bioremediation of naphthalene in water by Sphingomonas paucimobilis using new biodegradable surfactants based on poly (ɛ-caprolactone)

“…Insufficient biodegradation led to the accumulation of big masses of foam in streams and rivers. For example, the branched-chain alkylbenzenesulfonate (ABS) surfactants, which resisted biodegradation, were replaced by linear alkylbenzenesulfonate (LAS) surfactants, which are completely biodegradable (Ghazali, 2002;Kö lbener et al, 1995). Also, biodegradable biosurfactants have been used and compared with synthetic surfactants with promising results (Makkar and Rockne, 2003) on bioremediation applications.…”